According to the Apple tech specs page: No. One external up to 6K 60Hz. But, I believe you can connect a second external and it will mirror the other. This is a limitation of the M1.
If you need three displays, get a MBP (M1 Max) or a Mac Studio.
An M1 Mac can drive a total of 2 displays, so the Mini can run 2 4k displays. Laptops and the M1 iMac require the use of a Displaylink adapter to drive 2 external displays because you’re then at 3 displays.
An M1 Mac can drive a total of 2 displays, so the Mini can run 2 4k displays. Laptops and the M1 iMac require the use of a Displaylink adapter to drive 2 external displays because you’re then at 3 displays.
DisplayLink would, of course, not be a supported solution. Can you recommend a DisplayLink adapter and software which you know to work well with an M1 Mac?