Hey, so I know you can tap on a dock icon to launch the app, but when the dock is more than full and requires scrolling to shift the icons, this still cannot be done with the touch screen, based on docks I have tested. I tried the built in docks in Gnome on Pop, Ubuntu, and also Plank. None respond to an attempted drag via the touch screen.
Are there any less widely known ones that do? Are there any plans to bring this functionality to the dock in Gnome?
So, as I replied, stop using the Dock altogether. Spend the time to use one more click into the exploded view of all apps, and use touchscreen like that. It solves your problems with only one extra touch. Gnome is not designed as a mobile-style interface as you wish, but with one touch it does what you want.