TigerVNC fullscreen is stretched and split across both screens on kubuntu 20.04.
Looking thru all the "system settings" i don't see anything relevant.
Not a problem on lubuntu 20.04.
How do i get TigerVNC fullscreen on just one screen in KDE?
Im am on Ubuntu 20.04 Gnome but I had the same issue.
TigerVNC spreads the full-screen over all monitors by default.
You can change the seting inside TigerVNC viewer: press the menu key (F8) and go to 'Options...'
In 'Screen': uncheck 'Enable full-screen mode over all monitors'