According to Apple, the new M1, Mac mini, MacBook Pro and MacBook Air computers only support up to two 4K monitors simultaneously. But YouTuber Ruslan Tulupov has found that using DisplayLink adapters you can connect a staggering number of different monitors to the same machine, from televisions to 4K monitors, etc.
According to Tulupov, up to six external monitors can be connected to the Mac mini M1, and five external monitors to the MacBook Air M1 and MacBook Pro M1 using DisplayLink adapters.
According to Apple, the MacBook Air M1 and MacBook Pro M1 can use an external monitor with up to 6K resolution at 60 Hz. The Mac mini M1 can use a monitor with up to 6k resolution connected via Thunderbolt and a 4K resolution monitor through 60 Hz connected via HDMI 2.0. This means that each new Mac M1 can use one less monitor than the models it replaced.
However, Tulupov has found that it is possible to use up to six external monitors on the Mac mini M1, and five external monitors on the MacBook AirM1 and MacBook Pro M1, using a trick. It has achieved this by using DisplayLink adapters to connect the additional monitors. When the ports on the Mac M1s are full, the DisplayPort adapters are connected through an external dock to add new ports.
It is likely that this feature Apple wants to reserve it for the top models of the range (iMac and MacBook Pro) so it would not be unusual for a future patch to limit this capacity.