Just to check is

volume group luks not found

Boot error another cosmetic thing or is there a problem in my fstab/crypttab (note computer boots fine)

I agree, but it does show that it's a problem with your particular setup, what particularly is the problem and have you tried running from terminal

Gimp works fine on my system latest version, do they offer it as a snap/flatpak

https://forums.puri.sm/t/what-should-we-have-on-the-pure-browser-start-page/3792

gimp didn't come pre-installed on my system, but have you tried using a different image manipulator or an older of gimp?

is this a possible relation too https://tracker.pureos.net/T530

possible relation too
https://forums.puri.sm/t/battery-drain-while-suspended/2726/10
and by extension
https://tracker.pureos.net/T419