I didn’t see this comment in this thread initially, but I made what I think is a fairly detailed explanation of my biggest problem with iNaturalist Next in the linked separate thread. it’s at the level where I’m not able to use iNaturalist Next at all for my preferred workflow. I’ve logged out of and into the app again and will test it a second time just to be sure, but up until now that’s been my experience of in what way specifically it’s slow.
other than that, I second those who find the means of selecting the non-AI camera from a tiny icon in a cluttered menu to slow me (not the app itself) down frustratingly when using it, and following a notification to be quite slow to register it as read in the app.