SwitchResX 4 versions that were compatible with macOS Catalina are also compatible with BigSur on Apple Silicon Macs.
However most of the advanced features like disabling a display, rotating a display or overscanning a display aren't working with version 4.10.1 and below, due to the complete new architecture.
Version 4.11 (currently in beta) was tested on the only Apple Silicon Mac available (the Apple DTK) and had brought some of these features (disabling a display, rotating a display or overscanning a display) to the new architecture of the DTK.
The first reports on the M1 Macs show that the M1 Macs again use a completely different architecture than the DTK, which will probably mean that the 4.11 beta will not bring these features. I've yet to investigate again if this will be a definitive answer or if this can be worked around.