Mac Mini Sleeping When Idle
You have some errors in your power settings.


hibernatemode 3.  3 is the default for portables; since you have a Mac mini, this is incorrect; it should be 0 (default) for desktops.
standby 1.  If you don't want your machine to go into standby at all, this should be set to 0
autopoweroff seems to be missing. This should also be set to 0 as it's enabled by default.


Issue the command

pmset -a hibernatemode 0 standby 0 autopoweroff 0