I have an Alphasmart Dana that I bought on Amazon for $20 several years ago. It works great overall, but sometimes I need to reset it and restore my files from backups. (That's a common problem with older PDAs and similar devices, unfortunately.)
There was a pretty good article about the Dana published yesterday:
https://www.osnews.com/story/131180/the-alphasmart-dana-in-2019/One big problem with it is that the software to conect it to a PC is not supported anymore, but there are quite a few free apps for doing that. If you really, really want to try this, you can send me a private message and I can try to help, although I haven't done it in about 4 years.
There are some newer smart keyboards, but I don't know which ones are good (if any of them are). Here's one example:
https://www.amazon.com/KINGJIM-digital-memo-Pomela-Silva/dp/B07CYTVH4Z/You can find a few others mentioned if you read the comments in the article on OSnews, but unfortunately most of them require a lot of tinkering to set up.