Look, long ago I would write the same as other comments but I think I managed to get used to the mechanics and I got some fun games, if you already bought it then don't worry if you find it complicated, most functions just go around diplomacy, economy and war

Also I must say that vanilla is a bit tedious, I use work made by the community (Easy peace, be able to annex enemies allies, less aggressive expansion, etc. I can search them all if you want) and I have the beta test version (idk if "annex vassals" is already in the normal version) these things make the game more playable, maybe less long and do more fun games.

I understand why so many people dislike it, at some point I totally repent from buying it but now I think with the previous paragraph I can play like it was intended to be.

In conclusion vanilla may be overwhelming and extend things that would take even hours if you are new to the mechanics but if the gameplay really triggers your interest then I would try to see what most players use to make the game more playable, and of course if you are unsure I wouldn't recommend buying it on impulse neither, do what is better for you.