Mac Mini M2 SSD external drive connected via thunderbolt dock constantly disconnecting

Try moving the ssd drive to another thunderbolt port and see if it resolves this. If it doesn’t work try attaching drive directly to computer port other than thru dock connection if possible and try again.

Sleep is unnecessary for later Macs and should be disabled. Shut for long absences and overnights and use the settings shown here Wake up a remote Mac mini - Apple Community for regular use, should fix.

What macOS version are you running on the Mini?

What make and model is the Thunderbolt dock?

Do you have an issue connecting anything else to the dock?

I have the same issue - newer model Mac mini and tons of error messages. Seems to happen when awaking from sleep. Will try swapping ports to see if that does it.