And use Vorta if you want a gui for Borg backup.
What is your sleep setting in BIOS? I had some problems with Linux sleep that got fixed by switching to Windows sleep. Maybe try that?
I've been running mine on Unraid for the last 4 years or so, and I have no complaints. Probably you can't go wrong with TrueNAS either. The big advantage of Unraid, as I understand it, is the ability to add arbitrary drive sizes in the future, if you want. But you might not run into that benefit for a while...
Onyx Boox eink tablet that runs android does all those things. I use Moon Reader on mine.
https://shop.boox.com/products/noteair3