I agree the forum would be a lot more fun if we could discuss well made faction designs, sadly that is a rarity on the forum.
Hoop has made a couple of good ones, i believe myself to have made a good one but i think that is kind of it? There is a Persian one that’s also descent although it could have been a bit more focused on game design i think.
Like i still don’t really want a Chile but i still respect hoops attempt: Civ Concept: Chile (yes. really)
Like at least there is an attempt at cobbling together a design based on the countries history.
That said though it is easier to make designs based on countries with long and well documented history. Esp. if you are looking for solid ideas for unique units that aren’t just regiment names of otherwise relatively standard military units.
If you want elephants then Argentina is probably not the place to look, if you want a good cavalry faction then Poland is probably a good place to look at etc.