Brian Masinick
Are you able to boot into this system by any means?
Perhaps reusing the installation media you can attempt to do a boot repair, boot installation or equivalent action.
If all fails no matter what, I’ve found the refind boot loader / boot manager is extremely useful for booting numerous different types of systems, https://www.rodsbooks.com/refind/ is where you can find it. I keep a copy on media, just in case something goes wrong on one of my systems. I haven’t needed it much, but when you test as much as I do, it is a very handy tool indeed!
--
Brian Masinick
Alternate "Search B":
This search page