I think the problem is that even the best tablet is worse than a cheap shitty netbook. Shitty netbooks can be had for $200. The fancy shmancy backwards folding ones, (into a tablet form factor) aren't that much more.
You know what's better than termux? OpenSSH, tmux, a proper term, a proper tiling WM, in X.org. Or Wayland or screen if that's your thing I don't judge.