Sounds like maybe something is wrong with your space switch shortcuts in system settings => keyboard => shortcuts => mission control => mission control
Since you opted to put the MacBook Size and Release Year instead of the "macOS version" I'm just taking a guess here..
If you have MacOS Venture..
you should check under TrackPad settings, and make sure that "Swipe between Full Screen Apps" is not enabled. This uses the 4 Finger Swipe Left/Right Gestures
Thanks for your reply.
My MacOS version is 13.3.1 (a) (22E772610a).
"Swipe between Full Screen Apps" had been disabled when I hit this bug.
The workaround is manually set the correct key to these 2 shortcuts and it now works in Alpha version.