Have you tried
Outline?
I recently set it up and I'm very impressed.
Yes please!
But you never gave us cause for worry
Like a regular brain, but with RNG elements
Madness or brilliance
Set and forget
Best case scenario
Why am I still faster than you?
Lenovo ThinkPads work very nicely with Linux, and there's a large second-hand market. The T and X series are especially great I find.
The usual advice about avoiding soldered RAM holds in general, but right now used laptops are being bought just for stripping RAM. So I think putting up with soldered RAM in second hand devices (I'd go for at least 32G) can be a smart move because it may be a better deal (and often a smaller form factor).