Decided to go for more modern hardware.
Long story made short. Apart from the graphic invite never showing (just plain old vga text messages scrolling), on the first few installations, there were some random problems ranging from not shutting down to missing the Qubes system tray icon, but it was installing.
Some red lines in dmesg, apparently unrelated to the issue(s), since, more or less, the same messages were shown after installing Debian 10, and fixed with some firmware (iwliwifi, realtek, and the nvidia driver).
Now, installation is impossible. The hardware is detected until the the USB boot drive, attached as a SCSI device (5:0:0:0). The size, serial number and so on is displayed, then it freezes for some time before showing an endless "dracut-initqueue timeout" message.
I'm at a loss.
Just in case: Intel i7-8750H, GeForce MX150
I know this is the least of your problems right now, but since you mentioned it, I often had this problem after a fresh install, and finally figured out what is was. If Qubes is aware of available updates, sometimes it refuses to shut down. I literally had to yank the power cord, and remove the laptop battery.
After a fresh install, it is a good idea to one by one, manually update each and every cube, starting with dom0, of course. Then it will shut down.
Normally, I do a reboot after installing an OS, but not with Qubes. It wants those updates first, I guess. I may be wrong, but this works for me.
how did you create the install usb media?
so its a legacy boot ? have you changed the graphic settings in the
uefi-bios what are the options there