Rome:
Excellent logistics due to automatically built roads, fast initial advancement in cultural topics due to a free monument in each city, a good unique bathhouse building (replaces the aqueduct and gives +1 content), usually I try to do without aqueducts, but I almost always use Rome, firstly, the construction itself is cheaper, and secondly, contentment is never too much. A good unique unit is Legion, a kind of universal soldier, a very powerful warrior +4 compared to an ordinary swordsman, in addition, it can be used for purely civilian purposes =). He has a unique opportunity: firstly, he can repair looted improvements, and secondly, he can (one-time) cut down a forest and drain a swamp. By the way, he carries this ability through all upgrades.
Options for victory: in principle, any, but early military dominance is preferable due to a strong unique unit and good logistics.

Russia:
A huge territory when a city is founded is simply a HUGE plus, as a rule, all the most interesting cells are captured, it saves a lot of money due to the fact that you don’t have to buy up interesting cells.
Trade routes to other civilizations give +1 science or culture for every 3 technologies if you are behind in science or culture. It’s an average ability, but you can use it, focus on culture if there is a highly cultured neighbor nearby, like Rome or Greece, and at first steal culture from them.
+1 faith +1 production in the tundra, just a good ability.
A unique building - the Lavra, replaces a sacred place, is cheaper to produce, . Gives points to prophets, writers, artists, musicians. Nice building. Religion, if you strive for it, you will take even the most difficult deity second. Russia is one of the few civilizations where it makes sense to embrace religion and use it.
Unique unit: Cossack. Didn't use it =)
Victory options: the easiest way is religious on small maps (up to 6 civ). Cultural, ordinary through the rapid receipt of writers, artists due to the unique Lavra and theater square. Also interesting is the option of an early cultural victory through the belief of Power and the apostle-martyrs, but it has its own subtleties.

Greece:
Additional universal card political course. It's hard to come up with something more useful. Helps enormously, especially in the early stages of the game.
Victory over the enemy gives culture (the ability of the leader Gorgo). A very strong ability both at the early stage of the game and at a later stage, a good war in the Middle Ages-Renaissance Era can advance us from a Merchant Republic to a Democracy =). The unique ability of Pericles (+5% to culture for each overlord of the city of the state) is IMHO much weaker.
A unique building - the Acropolis, replaces the theater square, and is cheaper to produce. Only Russia and the Congo can create a strong building, a good bid for a cultural victory, and competition in the struggle for great writers and artists.
A unique Hoplite unit, an ultimate against Cavalry, but in a real game against the computer it is of little use; it is not often that the computer (except for the Scythians) builds masses of horses.
Options for victory: the easiest way is cultural.

Germany:
Additional military course card. Good ability. Worse than the Greek one, but also good, especially in the early stages of the game.
Cities are able to build 1 district more than the population allows. A German city with a population of 4 is capable of building 3 districts.
Unique building - Hansa (replaces the industrial zone), cheaper to produce, +1 production for an adjacent resource!! +2!! production for the neighboring center of commerce. The best, in my opinion, unique building, capable of creating very decent production even in areas poor in hills; with dense buildings, Hansa is capable of producing +6 or more production; Industrial zones can only dream of such production.
A unique unit is the submarine. Didn't build it =). Must be good.
Option for the development of Germany - definitely with all our might into apprenticeship, we build up with Hanse markets, study the Civil Service, take meritocracy + 1 culture for the built area, study Guilds, take artisans + 100% of production from the Hansa neighborhood. And... We get a huge production for the Middle Ages, further according to taste, set up the troops and demolish everyone, complete the campuses and go into space, complete the theater theaters and go into culture. Space and military victory are the most simple options victory. With this set of abilities, I believe that Germany is the strongest nation in the game.

Briefly about the rest.
Congo:
Double points for writers, artists, merchants, musicians. Computers even on the deity are quietly resting from great people. Congo has it all. Congo is the #1 contender for cultural victory.

England:
She is strong when everyone is weak =). If the map consists of small islands where one city is crowded and everyone has the same situation, England is able to survive and build due to the unique Shipyards of the Royal Navy. Shipyards (a building in the Royal Navy Shipyard zone) of England built on another continent give 2 production for no reason (other nations do not have such a feature), so due to unique Shipyards and virtually double the number of routes, England is able to organize a relatively powerful trade on islands poor in production - industrial empire. I once came across such a card and played it as a trade. accepted wild civics all for + gold from trade routes, drove all caravans to another continent and accepted colonial taxes (+25% to gold on another continent. My income rose to +500 per turn (without banks and exchanges) and the buildings I'm in I simply bought my own cities, since production in them was weak. In general, the nation is interesting, but situational. Options for victory - IMHO cultural or naval if possible. Of the maps, archipelagos are preferable.
PS: The patch killed England.

China:
Sort of average. Eurekas tear off 60% of the tech instead of 50%, this is probably the case, but it feels weak. The workers are of course very nice. It makes sense to build the Great Wall after the opening of the castles (it begins to give culture), but this is not the most interesting direction. A well-built wall can give 3 gold, 3 crops. After the opening of Aviation, the wall also begins to produce tourism, but you will not achieve a cultural victory with the wall alone.

Scythians:
By far the most powerful nation for military victory. Keep in mind that it has a bonus for building light cavalry until the end of the game. Build a helicopter and you get 2.

Arabs:
Another nation for which religion is necessary and useful. Strong with early universities, 10% buff to science and culture if your religion is in the city. At the same time, I would not get carried away with religious victory. Through early universities, rush into science and go to the stars, or at least early modern tanks overwhelm everyone.

Sumerians:
A very strong scientific nation. Zikurat is the most useful unique territory improvement. +2 science +1 culture without technical requirements, this is VERY cool. Due to this, we quickly become leaders in science at any level of complexity. The unique unit is also very good. Inexpensive to produce, very strong for the early stage, with good mobility, does not require maintenance. The options for victory are military, due to more technologically advanced military units, or space.

Poland:
Strong nation. Jadwiga's ability to turn a military course card into a universal one is very cool. In my opinion, this ability is even more useful than the additional German card. This ability makes Poland one of the top contenders for quickly gaining religion.
Unique structure - Cloth stalls (replaces the market) give +4 gold to domestic trade routes, +2 production for international trade routes. The most powerful building in the game.
The unique unit is very good, although it may be difficult to quickly produce it.
Relics give +2 faith, +2 culture, +4 gold. An additional incentive to go to religion, mediocre ability. The remaining features of the nation are, to put it mildly, nothing =).
The cultural seizure of cells by forts - camps (you cannot squeeze out a cell that has already been captured by cultural influence) is simply irrational; it is easier to simply buy the necessary cells.
Options for victory - religious, military.

Aztecs:
A very strong military-expansive nation. The nation does not have any bonuses to the type of victory other than military, but it is able to deliver 50% more cities without losing contentment.
Luxury resources provide food for 2 additional cities, +1 to the strength of military units. A very powerful ability. It contains all the power of the Aztecs. The fastest, aggressive early expansion to luxury resources and their instant processing, a very early war and the capture of slaves by eagle warriors is the key to victory.

Brazil:
I didn't understand this nation. In theory, Brazil's strength lies in its endless expansion. Brazil, due to its unique region, is capable of placing any number of cities with a population of 8 without losing contentment, but I don’t see any benefits to the type of victory.

India:
Complete rubbish and confusion. It would be interesting to listen to the comments of those who gave India national bonuses and what its strength is. All the characteristics of a nation are based on religion, but it can only acquire religion if it is lucky. A unique improvement makes it possible for cities to grow quickly, but where can they get enough for them?

Perhaps I described everything a little clumsily. If something needs clarification, ask, or criticize, objective criticism is always useful.