My personal choice would be the Romans. Reason being that they have strong melee unit base, and solid cavalry. Their ranged units are lacking, for the lack of a better word. Marian Reforms unique tech can be powerful when timed correctly. I prefer their playstyle the most, and their units are very detailed. If I were more objective, the choice would be either Seleucids or Athenians.

I feel very tired, unlike with other things on my PC. Why could it be?  Are my settings correct? What I can do to fix it?

I could manually scale down the hidden faces before packing

What do you think is the best civilization in the game currently? You can say several criteria, personal choice, the most powerful,... And what is the functionality or unit that you preferred and which has disappeared. I have been playing 0AD for over 9 years now. Thank you for your work!

No warnings in log (if we're talking about those texts that show on the top left corner when the game becomes bugged). I haven't tried disabling GPU skinning, I don't remember ever tweaking with it. I've switched to Vulkan rendering ever since I downloaded A27 a while back, my GPU worked fine with it (I'm using a mac catalina). I really wish I was able to play A28, Delenda Est seems to be back, I think it's a great mod.