M1 mac mini to imac 2012 Catalina

Nope, as the others have said that will not work. You M1 MM is not compatible with Target Display Mode which has been dead for years now. Your MM needs an external display, they start at about $100. Please carefully read Target Display Mode (TDM)

It is not possible to use the iMac as a display.

For a display, the LG UltraFine 4K Display - Apple or the LG UltraFine 5K Display - Apple are great.

Cheers,

Jack

Welcome to the Apple Support Communities.

If you are trying to use the iMac as a display, you cannot.

Jack

What cables do you need to do what?