I’m having the same issue as what’s listed here (but closed out in 2017!):
NoMachine Forums – Full screen on Mac
Essentially, in full-screen mode, the top Mac menu bar isn’t hidden properly. It usually is the menu bar for a different app (the one I just switched from) and it covers the top part of the remote desktop display, making it impossible to get to. Same thing with the Mac dock if I have it fixed at bottom. Sometimes I can resolve by swiping to a second desktop and then swiping back to the NoMachine remote desktop (but if I use the dock icon or CMD-TAB to switch to it, have the problem described).
Also seems to affect the settings screen that can be brought up by pressing Ctrl-Option-0
I was using client 7.0.211 on MacOS Big Sur but upgraded to 7.1.3 with same results. I also tried hiding my MacOS dock and using uBar 3.0 dock with same issue.
The server is running on 7.1.3 on Linux (Ubuntu)