laptop

Get an old laptop

Why not a PC?

PCs are immobile. Ideally, you want your laptop to be with you always in a comfortable bag, so you can pull it out on a whim.

choose business class - old Thinkpads are the gold standard, but I've heard ok reviews about Dell Latitude.

Why old?

If you're fine with the modern built-on-booger 5 micron plastics and keyboards with no key travel, you can get a new laptop-as-a-service and buy a new one every 2 years when its obsolescence plan runs out.