Wish there were better options than those... Other than the uConsole, handheld computers with thumb keyboards seem to be in the category of literally handmade cyberdecks.

https://hackaday.io/project/202522-cyberdeck-handheld

https://youtu.be/u8kYHgKKhjY

https://youtu.be/IB5OJr_MimQ

Trying to make my own too. Ordered some prototype keyboard PCBs. No idea if I'll get anywhere but I'll try.