Most UIs are not optimized for touch, but if you use one that is like GNOME it will still have issues. The onscreen keyboard is not outstanding, you essentially need wayland apps for modern features like touch scrolling etc, and there will be bugs. For me the main bugs are some GTK popups will cause them to crash when typing into them on virtual keyboard, and swiping through apps doesn’t work very well on debian. If you use a different de or distro, your experience might vary.
You might be interested in a raspberry pi or similiar arm board, they are generally more power efficient.