GrapheneOS developer is very toxic, if you trust him is up to you. I prefer not running his code on my personal devices, especially after him blaming large parts of his community for coordinated harassment. Watch Louis Rossman’s video on it.

Although for security-focussed custom roms on the google pixel, like Calyx or Divest, you can re-lock the bootloader, so there’s less security risk. A factory reset is required to unlock it again, similar to a factory bootloader lock.

Linux, it fits my needs better on desktop, and is much less painful to troubleshoot than Windows, with more freedom and control than macOS.

I think the last thing you’d have to worrh about is your job when nearly all infrastructure collapses.

Depends on how it’s implemented. Anyone using a “media proxy” will see their discord bridged media probably fail to load (outside of possible caches) after a day. Anyone who has their bridge configured to reupload discord media to their homeserver should see no change.

You want a magic Discord speedboost? It’s called OpenAsar. Mitigates telemetry, and speeds the client up to usable levels, especially on lower end hardware.

“Android” phones can sometimes have “close to mainline” Linux distributions flashed onto them. You can get some of those, used, for less than 100$.

A custom Android rom would provide you with a decent chunk of the freedom you want in a mobile device.

A phone specifically built for Linux, with as much as possible FLOSS firmware, will cost a lot more. The cheapest is probably the PinePhone.