My Mac Mini keep shut down randomly and often crash with green screen with watchdog expired

Any solution? I have been contacted by Apple and told me that I am not the only one having this issue and they promised an update soon. I did the latest updated in August 12th 2021 but so far it seems getting even more often with random shutdowns at night when it should only be on "sleep mode" and often crash with all green screen and restart himself. I know that the reason might be the external driver ( I have tried two so far, WD 2T and a TOSHIBA 2T) but what's the point of having a brand new Mac Mini if using an external driver make this chaos? I do work often with iMovie and Photoshop and it's painful when you are working, posting on web long videos and get suddenly a crash. Can you guys fix this bug? You are Apple! I do use Apple devices since 2008 and never had a problem with any of it but this Mac Mini.....I would rather don't buy it at all if I knew that all I get was this mediocre device. Very disappointing.