why is my mac book pro desk top shutting down automatically?
why is my mac book pro desk top shutting down on its own then restarts only when I unplug and plug it back in?
iMac 27″, macOS 12.7
I suggest you start by identifying your exact model Mac because a "mac book pro desk top" is a contradiction in terms.
If you are asking about a 27" iMac as your profile indicates, then an SMC Reset is justified: Reset the SMC of your Mac - Apple Support