I like mods that keep the vanilla art style and 'feel' but I don't use several mods at a time because it can feel unnatural. I mostly play single-player Hardcore so I like mods that update the vanilla features rather than add too much stuff. But vanilla is great fun too!

Mediumly modded : I am a creative mode player so I am of course using some quality-of-life mods such as WorldEdit, both Xaero map mods (plus Better pvp) and the built-in FPS HUD of Sodium. optimisation mods (Sodium, Starlight, Ferritecore) and finally the Minecraft Transit Railway and it's unofficial additional mods such as the Joban Client Mod or Station Decoration addon. If the loading time isn't too long, I will add the Yuushya Townscape mod (a decoration mod far from the Vanilla design that focuses on appearance over functionability, it also adds precise move and rotate options for blocks).
This light choice of content-adding mods is due to the bad performance of my laptop and the version I play (fabric 1.18.1 or 1.16.5).

Depends what mod and what the game offers. Also the fact that I am able to play on mods is crucial for my gameplay

I really enjoy a modded experience so that I am able to architecturally build as well as import art

I like a "lightly" modded version which is why I run The Vanilla Experience. Close enough to vanilla to retain the feel, but with some useful things and a little "pizazz"

I enjoy vanilla more. Modded often feels kind of weird to me. Perhaps it's that mods don't really feel like a complete part of the game.
Don't know if anyone else can relate...