Antoine Budgie will not change to QT, It will use EFL for it's ecosystem, leaving GTK+ behind... maybe next iso release you'll be able to install KDE Plasma.
This may be a problem with noveau and KDE, and your card will need nvidia proprietary driver to work...
If you have hardware experience, and still want to install KDE Plasma, and you are feeling confident enough, you could remove your nvidia card, install plasma with the ryzen onboard gpu, update the system, and re-insert the nvidia card again.
It's not easy if you have no experience with hardware, you could burn or break something really expensive, so don't do that.