I have a Dell Optiplex 3060. i5 8th Gen. Installed a nvme 128Gb SSD.
I can get the machine to boot from a USB, which sees the SSD and goes through a seemingly sucessful install.
I remove the USB as instructed, restart and end up back at the BIOS page. I can the SSD under system config, but no matter what I do, I can’t get it to list as a Boot Sequence option.
Yes, i did, and it was a similar Dell, a 3050 with a 6th Gen i5.
All i can add is that i installed ROCK on the m.2 NVMe with it being the only drive installed at the time.
And the m.2 stick was brand new and BIOS identified it just fine, beforehand. (A Samsung 970 EVO Plus, 250Gb)
Please clean out yor BIOS setiings also, clening any boot keys and disabling secure boot!
And i suppose you should enable Legacy boot (and disable UEFI)