Having multiple monitors with different refresh rates on X11 just isn't a thing(*). I would disable your non-primary monitors and validate that that the single-monitor situation works before moving on to trying to figure out how to get a better multi-monitor experience
#Manjaro + KDE Plasma (X11) - Games capped/locked at 60FPS or 60Hz + screen tearing
vagrant nimbus
vagrant nimbus
It's complicated, but it's mostly true with a few buggy hacks that make it kinda sorta work sometimes. Aka why Wayland is the solution. Eventually.