This doesn’t answer your question properly, but a few years ago when I moved away from the YouTube front end (I use FreeTube primarily), like you I initially missed the recommendation algorithm (more than I thought). But the longer I went without it, I realised that the recommendations were really fuelling a kind of mindless addiction, eventually I started to watch fewer but higher quality videos, usually based on what other humans had recommended to me and I’ve found that to be a much better experience overall. Remember the algorithm is designed to keep you on the platform for as long as possible, not necessarily to give you the highest quality experience.