I'm starting to feel like the most promising units for these types of computing experiments are extremely cheap commodity stuff -- $40 used Chromebooks, old Android phones https://social.omar.website/@omar/statuses/01HTZFTDK6P0NC2QY7Z6ATR4M1
which is funny (ironic?), because so many computer people I know jump straight to iPhones or iPads when they think about portable computers I could use, because that's what they use day-to-day