Bookorbit has a request feature since somewhat recently (tested it a bit and with search on MaM for English books I’ve gotten a 100% hit rate so far)… However its probably the project you mentioned as vibe coded and the dev has some controversies (they also made booklore which imploded spectacularly). It also has a ton of great features to sync with ereaders etc. I’ve been running it to manage a pretty big library and its been pretty solid.

I do sometimes use the AI feature where you opt in to the AI overview. I’ve found that though the AI behind it is rather basic (same with the chat), its still decent when you want a quick answer instead of SEO slop (at least when you dont care for perfect accuracy).