I’d actually missed that there was a floating panel, and it works quite nicely if you allow apps to appear below it.
Wayland will be interesting as I heard it was all ready for KDE apps, but last thing I also heard was it had some issues around Nvidia support. So not sure if it is fully ready yet for gaming with Nvidia, but I had made a note to test it again when Plasma 6 went live. The point was though that all current development attention is going into Wayland, and X11 is no longer really getting attention to sort issues out.
This does sound promising, though: “rest assured that the KDE devs are working on addressing all the Wayland/NVIDIA issues before Plasma 6 hits the streets in stable version”.