The installation on an older iMac/64 two months ago was quick, easy and successful just with the USB-Stick generated by Etcher. I tried out the System for a while, but it is not possible to switch off the Monitor. This consumes too much power over time.
Then some weeks ago I odered a M4 and so a MacMini buildt late 2018 is left now.
But I can’t install HA on this machine! 
The USB-Stick with HAOS installation is not recognized by the Startup-Manager.
First I tried proxmox. Might be a comfortable system, but only if you have a 1TB SSD on the Mac. I have only 256GB which is just enough for HAOS and a Linux VM. So I tried to expand the volumes over a external HDD. This requires proffessional knowledge of UNIX and VM machines as there is no GUI for formatting, partitioning and volume building 
. After four complete re-installations I finally gave up.
Second tried a direct installation via a Live-Unix: restore from .iso as well as via Balea Etcher. Installation was done, but the System is still not recognized by the Mac.
Now I am thinking of installing a supervised version. I installed Debian KDE (which shows as “bookworm” during installation). Is this Version supported by HA? If not which version is the supported “bookworm”?
There might be someone out there who was successful and might share his/her experience?