Can't access Recovery Mode (2011 Mac Mini)
If you have an bootable macOS installer USB (Here is how to make one), boot from the installer directly by holding Option Key.  

The options would require having access to a Mac (VM or real)

Another option could be to install macOS on an external drive and boot from it(holding option while booting), and try to install macOS on the internal disk. 

Third option could be, remove internal disk from the MacMini, get a 2.5inch SATA to USB adapter, install macOS on the "external disk". Reinstall, and auto boot from the newly installed macOS HDD(or SSD). Might be a good opportunity to upgrade to a SSD.