Not sure if this is the correct place, but I found this suggested fix for Dual Image comparison in Shortcode UI, which works well on desktop, but not on touchscreens:
https://github.com/getgrav/grav-plugin-shortcode-ui/issues/42
Specifically there's some .js code for touch events (which I'm not prepared to try) and a suggestion it should go through as a pull request. That was over four years ago, so I assume it either didn't fix it or nobody did the pull request. Is anybody familiar with this and can possibly look into a pull request?