Valve's Steamdeck uses Plasma for the Desktop Mode. It's still 5.x though. I can't wait to see it get updated to 6.1. The Plasma teams really has been putting in lots of ease of use improvements.
Nice! I recently perma-switched to linux and KDE has come so far from its v3 days, where to be frank I just didn't like it much. Definitely enjoying it now though. Its very usable, customizable, and mostly consistent.