Not OP. The usb will add two boot options to the bios menu and grub installation failed with an error if you choose the wrong one. Everything else will work fine, but the installation will fail right at the end. The installation program will tell you to retry installation when that happens, which is kinda weird, because that suggests that they were encountering non deterministic errors when developing the installation program, and it wouldn't have helped in my case anyways. I would've gotten the exact same error message again.
No error. The installation seemed complete in some instants (way faster than Ubuntu or the previous Pop OS on the same machine), then GRUB would say it can't boot (I can't remember the exact phrase though but the fact it was GRUB suggests it's not about "secure boot", it was switched off anyway).
> but a wiping the disk and setting up partitions again fixed it.
In my case it didn't. Perhaps I should try some other way, e.g. text-mode fdisk.