Love that you mentioned Libredirect! I don't like how maps redirects to OpenStreetMap though, why not just redirect to Duck Maps, which uses Apple Maps.
I just watch YouTube signed out in Safari. It is very easy to build your algorithm from there. I don't mind the ads since I don't watch YouTube mainly on my phone and I occasionally clear cookies.
You can also install Orion Browser, made by Kagi creators of a privacy focused paid search engine, which supports Firefox extensions like uBLock but I don't think it is open source right now but It will be soon.
Get a new phone number and never sign it up on anything. It is very easy to replace a phone number. If you have had a phone number for multiple years and signed it up multiple times and still using it, it is time to change it now.
Blocking somebody on social media doesn't really mean anything, they still have your account, can still see your posts, comments, and even liked videos if they use another account. You would have to delete your account if some random person has your personal Instagram that you don't want anybody knowing, even if it is private.
X is unusable without an account, It always nags you to make one no matter what.