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.