Linux has been fine as a desktop since i386 days.

GrapheneOS is very easy and smooth, but only works on Pixel hardware. LineageOS is more rough around the edges and considerably less secure.

GrapheneOS is a lot more smoother experience than LineageOS.

You can use a MiFi router with tablet and a dumbphone just for calls.

I have been using custom ROMs since CyanogenMod and am currently mostly on GrapheneOS, some of it entirely Google-free.

Thanks, it is enough for me.

Yes, when I buy books on Amazon it’s the dead tree kind.

Yes, KOReader and Librera FD are two applications I use currently.

I’m limiting myself to only open source applications on the tablets. Strictly nothing from Play Store or Aurora.

No, you could never buy books on Amazon, only rent them. Calibre with DeDRM plugin was a poor way to liberate them, given that formatting in libre formats was often worse than the original.

I stopped doing that and ingnored the Kindle ecosystem in general. I tried a Kobe reader with .epub books from diverse sources but I mostly use tablets (LineageOS and GrapheneOS) to consume content these days. The reader apps are not that great there, sadly.

Just use NFS then.