See, I've actually enjoyed the vanilla game so far. Keep in mind when I say "true vanilla experience" I'm referring to the balance and general mechanics of advancing in the game. I've installed a huge amount of stuff that improves the game aesthetically and adds to immersion, but I'm not going to touch something like FCOM, or even probably TIE, until I do another playthrough. Which may happen right after I get bored with my current game, but I'm advancing at such a glacial pace that I'll be sticking with it for a while still. I got the game, like, 9 months ago now, and my character's at level 16 (with maxed endurance woo). I've literally put more time into mod-related stuff than playing at this point, haha.
I'm thinking when I installed the Unique Districts I was trying settings out that were killing my framerate anyway, so it was already dipping down to framerates in the teens before I installed it and I kind of interpreted that as being the mod's fault. Upon uninstalling it and seeing my framerate was still terrible I fixed things, but haven't had a chance to try it out again. I've got a few other mods I want to try that beautify cities, since I'm not doing Better Cities this game, and right now the most I've done is installed the mod that adds morning glories to the walls of Anvil. Also improved wayshrines, which isn't a city, but all this stuff falls under Expansion->Environment on my mod website I intend to hype exhaustively until I finally launch it, haha.