both Gnome and Plasma support touch, so try em out and see which you'll like more. go for the freshest distros so you have the newest versions of either as touch is being worked on constantly.
not sure if you'll be able to actually use the thing without an external keyboard/mouse; case in point, Gnome for the longest time didn't allow touch to initiate dropdowns in the UI, kinda big deal.
be sure to not use greeter logins and disk encryption as the on-screen keyboards (OSK) don't work outside the DE. also, issues with non-US keyboard layouts.
just a warning, if you've used an Android or iOS tablet, the support is pretty basic and the experience and performance is nowhere near that level.