I’m exactly like you and looking for exactly the same kind of device : very good (ortho) keyboard, small screen (e-ink for better visibility in the sun and battery).

I’ve written about my quest here : https://ploum.net/the-computer-built-to-last-50-years/

Unfortunately, I’m really angry against Astrohaus for the Freewrite. Their software are a shame, force using a proprietary cloud and are full of bugs. My Freewrite, despite its weight, have no more battery than my laptop. The traveler has a very very bad keyboard to the point of making it unusable for me (I had to send it back because some keys were always quadrupled. Now, the space is only working if I press it really violently). See gemini://rawtext.club/~ploum/2021-10-07.gmi

Placing all my hope on the MNT Pocket even if I would need to adapt my layout to the keyboard. Hoping to see an eink version soon to use with only a terminal. Neovim, Neomutt and Offpunk are all I need 95% of the time ;-)