Some additional thoughts that may help get to a cause. There is this which does more to address installation issues as opposed to boot issues.
Do you boot to emergency mode or does the boot process stop at Failed to start Switch Root?
It might be a problem with grub2 but more likely some kernel parameter needs to be added or removed from grub2.
It will be helpful to have some hardware information on the computer where the failure occurs. If that computer has a system that uses inxi the command inxi -F would provide a good bit of detailed information. Any really new hardware could be a problem or graphics possibly could be, especially nVidia graphics. It is is a graphics problem you can try booting in “Basic Graphics Mode” under “Troubleshooting” on the ISO’s grub2 menu.
Another possible problem is with nvme ssd’s sometimes needing a special parameter. These are also under “Troubleshooting” they are the (PCIE ASPM=OFF) and (NVME APST=OFF) options. Also under “Troubleshooting” there is an option to boot the ISO in cli mode that may be useful for problem solving.
Also you could try this ISO and see if it will boot:
Rolling is as the name implies a Rolling release. Not yet publicly announced but internally we have been using this since OM Lx 4.0 and it generally is very well working. Public release is to be soon. The current hold up is problems with our main QA tool. There are folks working on these problems.
Note: Seems we need to add some documentation or “How To” about ISO boot issues to this.