You can have as many community folders as you like; only one will be used by the sim, and that will be in the packages folder that you pointed the sim to on installation. (I believe you can change it afterwards but I’ve never tried.)
I have two: one in the default location on C: where the sim is installed, and one in D:\FSPackages, which I created myself.
The one in the default location is unused and remains empty. Maybe the sim expects to find it there so I leave it alone, as it doesn’t use any space.