5800x, 5900x and 5950x will all be close to identical for capture age I bet.
I have a similar CPU to a Ryzen 5 2600 (and 32gb of RAM, and an ok GPU), and your PC performs a lot better than mine at capture age Memb. I would be surprised if OP doesn't see a big improvement.
I would check the discord to be 100% sure but I think yes - a 5600x would be nice if it's compatible with your motherboard.
The other possible solution is reducing your monitor's refresh rate but that doesn't seem to do much for me.
The civs could be a coincidence, he seems to be picking Indians and Goths a fair bit lately (before and after your games), and he regularly picks the same civ 2 games in a row then switches (which he did here, G1 vs Vilager he goes Indians, G2 Indians again vs you, G3 Goths vs you, G4 Goths...
That's not D-K effect.
D-K effect is in play, in that the "high performers" in this thread are "underestimating their skills" and figure everyone can get there.
I agree that it's incredibly difficult (2k+ is more like top .6%, not 2%) and most couldn't get there.
I do think the strategy/intelligence is at times overblown (for instance, in tournaments the decision by pros about whether to drop TCs and how many, often seems random). And Viper can meme...
Wouldn't feudal only mostly be scouts and archers (eventually at least)? So 44% bonus on one of the two main units. So yeah, I kind of agree Burgundians not top 2. Not Eth either. Sicilian bonus doesn't matter in scts+arch battle either.
Turks, Persians def up there. Indians with a good dark...