Oof, the question that I don't think there's been a fully good answer to in quite a while but the current list of gallery sites I'm aware of (and what I know about them if anything) is:
Deviantart: Large user base but it's being flooded by AI generated images and due to being shifty in the past about using creator's images to train AI models, and I believe now requiring people uploading art there to turn off permission for that on a PER-UPLOAD basis instead of gallery wide, I doubt it would be the best pick. https://www.deviantart.com/
Furaffinity: Stable, old enough to have a big user base, and they've put a ban on AI generated images in place. Sadly after the recent passing of Dragoneer it's future may not be as solid. It's impossible to say presently due to how recent that is and whoever runs the site going forward may not have the same intentions and what it presently is may change. https://www.furaffinity.net/
SoFurry: I know nothing. https://www.sofurry.com/
Inkbunny: Another one I don't know much about. https://inkbunny.net/
SheezyArt: Has the ability to customize your page in a lot of ways including panels/modules that can contain a wide variety of content. One users page will often look very different from others due to this. Allows users to set icons from their other social medias/websites/kofis etc on the top bar and even includes the Cohost icon in the options, which makes it easy for people browsing your art to locate you elsewhere. May not have as many users as other gallery sites yet as its pretty fresh. https://sheezy.art/
Weasyl: Another that I know little about, sorry ^-^; https://www.weasyl.com/
Not much to go on I know, but hopefully this will give you some things to research further. Good luck! ^u^