AFAIK Flatpak does not support systemd services (only systemd user units supported). However the Veyon Service is required to run with root privileges and interact with the systemd logind manager. So all we could package is Veyon Master which wouldn't help that much since you'd always have to install the Veyon Service (and Veyon Configurator) additionally.
oh... Was about to ask the same thing about using a Snap package but I'm guessing it would be the same.
Hi, the bios option is probably configured as you mention.
You can check the boot order by starting each machine in bios option mode.
Then you will be able to put the hard drive in priority boot. Unless the PXE option is used for some other reason...
I do not yet know this product so all I can suggest is to try building Veyon from source on this platform and see how it works. In general compatibility with recent versions of all major Linux distributions is quite good.