The Mac is going through a transition from Intel to home-grown M-series silicon. As a result, services and apps have to be re-coded for the new chip architecture. The newest company to do so is Synaptics which has now added support for its DisplayLink Manager on macOS. The manager tool will allow display rotation feature on M1 Macs; a feature support which has been a longtime coming.

Most applications work on M-series based Macs without having been re-written for the new architecture, as Apple has added a translation environment/emulator which allows Intel x86 apps to run on the ARM architecture. The new chips put the Mac in line with the iPhone and the iPad which also run on ARM based chips (A-series).
M1 MacBooks officially only support one external display
The executives at Synaptics have said that the new features will be available as a beta at the moment. The final version of the software will be launched sometime in “late” December. However, the company also goes on to say that the final release will only happen if all the beta tests are successful.
The DisplayLink adapters by Synaptics allow users to connect multiple external monitors/displays to the Mac. At the moment, the M1 Macs include – the MacBook Air, the 13” MacBook Air, the Mac mini and the iMac. Apple officially states the M1 MacBooks only support up to one external display, multiple displays can be used using DisplayLink.
A user on Reddit has shared an image (screenshot) of the working of the new DisplayLink Manager for M1 Macs. The beta version of the app allows M1 Mac users to connect docks or DisplayLink adapters to use external monitors in both landscape and portrait orientations.
The recently launched 14” MacBook Pro and 16” MacBook Pro which are powered by M1 Pro and M1 Max chips, officially support multiple displays.