I'm on the M1 MacBook Pro 16 gb model, too and have the same thing. Freezing, beach balls, and freezing so bad I can't invoke force quit.
When I'm watching video, the screen will freeze but the audio will continue, then sometimes the video will start up again, sometimes the startup screen appears and I have to enter my password. A couple of times, I had to force shut down and restart.
Weirdly, the system doesn't give me any error messages or crash reports.
My 2019 MacBook Pro was rock solid. I'm thinking to return this lemon and wait until Apple gets their act more together with the M1 chip.