The idea I’m thinking of is some kind of fliphone combined with a separate device for everything else. I haven’t looked too much into it so I can’t guarantee it’s a good idea, and after like 2 minutes of searching I couldn’t find a flipphone that supported hotspotting.
I just got GrapheneOS, and while it’s good I really hate the jumpscare that is the Google logo every time I reboot (since it’s exclusive to Google Pixels).
Remove YouTube Suggestions (assuming you still use the YouTube client directly).
Also, Tampermonkey, to install single-site scripts that you can customize and with more limited permissions.