So i watch youtube a lot and i am now using invidious, i can subscribe to all my previous channels but what i am missing a lot is the recommendation algorithm, like it would show me different videos based on my interests etc and finding new content would be easy.
But this would also mean my data would be sold to companies.
Is there something similar for these youtube frontends which can recommend me stuff without sacrificing my privacy?
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.
If you have an android phone, you have plenty of options. There YouTube revanced, freetube, newpipe, music and plenty others. They all have recommendations and are front end of the YouTube app.
Even Firefox on android works pretty well in my experience, with the sponsorblock and video background play fix addons (Fennec, Beta, or Nightly branches)
That's what I use at night for my videos that help me sleep since it never seems to crash or drop connection
I used LibreTube for a while, and I really preferred many things about its GUI and recommendations, but I switched back to NewPipe because I found myself having to fiddle with it too much to make it work. For example, if one instance isn't working it's easy enough to switch to another in settings, but it doesn't remember your login details for your NewPipe accounts, so I felt frustrated that I'd then have to launch Bitwarden and copy/paste my logon info every time.
If you're not concerned about your NewPipe accounts and only want it local to your device, it's not a problem, but I like to try to make things like my history sync between my phone and in browser on PC. (Probably not ideal for privacy, I admit.)
Youtube's search algorithm used to be great and you could just search a topic and get good results, now it is hot garbage just like the recommendation algorithm. So just subscribe to more people?
I wish there were a way to filter out monetized content. Sometimes I just want to watch some absolute rando raving about things from a shitty phone camera.
Block tube extension has been great. I found that I didn't need to block that many channels to start having content show up that isn't from the big YouTube channels. For example tech and game searches heavily promote big channels and dominate the first several pages of search results, and suppress little ones. But, then block some of them, and suddenly it's more of the regular small YouTube channels over the YouTube as a business channels.