Alternative IO devices for programming outside?

I want to spend more time outside so my myopia doesn’t get worse. But I want to be more free than having a screen and keyboard all the time.

Phones are good for consuming content. For development, if I know the code well enough, I can print some code on paper, imagine the changes I’ll make, and spend less time on the screen.

I just don’t have any tricks for when I’m unfamiliar or trying things out, like finding out the best way to refactor something. Then I really need to spend time, but at least, I want to try spending this time in varying body positions so I’m not hunched over in the same position, alternate input devices so I don’t have to sit down at a table with the laptop/keyboard. Any ideas?

Like building your own cyberdeck like the people on Reddit, maybe?