For proper desktop Linux in that price range a used surface is a choice. It’ll be bigger and less battery life than an android tablet and I don’t know what the fan situation is in the generations in that price range now.

Another option is go with an Android tablet that has LineageOS support. You get fullish access to the system, but the system is still Android, so depends on what you want if that works for you.

No idea if it’s any good, but here’s an e-ink watch: https://www.crowdsupply.com/sqfmi/watchy