Get back to MacOS

[PecanBrown]

Have 2015 Mac mini, 8g RAM, 1T HDD.
Wanted to set up as a home server. Did some research about home servers, networks, linux distributions. Installed Unbuntu 20.04. LAMP.
As I learned more info, I could not figure how to do, so I would reinstall the software several times. Everything worked fine until Ubuntu would NOT accept my password. I reinstalled Ubuntu several time with the same result.
Have tried getting into Recovery using CMD-R, option-cmd-R, shift-option-cmd-R with no result. End up going to <GRUB>.
Have tried redirecting files in system with (hd0,gpt1) not exactly sure if I got the info correct in the parentheses.
Have tried to install ‘wipe’, ‘Srm’ which GRUB do not understand.
I am LOST. PLEASE help.
Thanks in advance.

 

[Raz0rEdge]

You've removed macOS completely and replaced with Linux. None of the traditional macOS-based recovery options will work, since you don't have macOS.

If you can't figure out how to get your Linux distro working by visiting Linux-specific forums, then get a bootable installer for the version of macOS that you can get access to and re-install macOS on the mini.

You might want to research NAS for your server needs.