I haven’t logged into my Reddit account since June.
I never used Twitter, so that wasn’t an issue for me.
I just stopped using Discord, if I need to message someone on the internet I suggest Matrix but I almost never use it.
I mostly use Odysee and Nebula to watch videos, if I need to use YouTube I use alternative front-ends like Piped or LibreTube. I tried PeerTube, but there’s just not enough content that I would want to watch.
uBlock Origin has built-in bypass mechanisms. No extra userscripts required. Other extensions or scripts might interfere with uBO though. You also need to use Firefox or a Firefox fork like LibreWolf because Chrome soon won’t support MV2 anymore which is required for proper ad-blocking.
On Android, I recommend the UntrackMe app. It basically does the same as LibRedirect. You can also use this hack to install desktop extensions like LibRedirect in Firefox Mobile, it requires Fennec Nightly (essentially the Firefox beta version) or Mull (hardened Firefox which is built from Fennec Nightly) though.
It doesn’t allow you to lock the bootloader meaning you can’t use Android Verified Boot. There are more security issues with LineageOS, you can read about them on this site