I have been unable to get TotalSpaces 2.9.9 to function in High Sierra. It reports 16 desktops but will not allow any change. I can get to go to a single column of three (only that no other configuration) but when I attempt to change it it still reports 16 as being the max and doesn’t allow the change.
I am having the same issue in Big Sur.
I also have this problem in Big Sur - when I try to increase the number of desktops beyond 9, it comes up with an error message saying the max is 16.
See https://discuss.binaryage.com/t/totalspaces-support-on-macos-11-big-sur/7665/93 for a work around.