Nobara pretty sick though, but need some tweaks to make it stable.
I have learned that KDE multithreading render is not friendly to the nvidia graphics driver and I decided to use single-threaded instead. After reboot it goes fine and not lagging anymore to me, not sure crash frequency yet
Btw I was used command kcmshell6 qtquicksettings to open the plasma rendering settings, and change render loop to non-threaded (my desktop is using zh-TW language, not English, just dont choose "threaded" it meant multi-threaded or Automatic), then click ok and reboot (I have no idea why just simply restart plasmashell doesnt apply).