I would've recommended my instance which is metapixl.com but I'm also shopping around as I'm not sure if I want to stay there, but it's decent enough (having issues with the alt-text character limit but otherwise it's fine). The flagship is pixelfed.social which is huge now but they do get first round of stable releases, but regardless there's a list here https://pixelfed.fediverse.observer/list - filter by signups to yes. Most of them are general instances so other than the non-english one I don't think there's a problem to pick. ETA: oh wait! Check their abouts, some of them allow nsfw content (which shouldn't be a problem until u check local feed)

ETA: I would recommend metapixl.com regardless because they offer the cushiest amount (max 20 pix; caption length is max 2k characters; most others will put about 5 pix with max caption of 500 chars)