Comment # 1 on bug 1182592 from Neil Rickert

Just a general comment.

When you install 15.3, you should indicate which build.  You should also
indicate whether you used the DVD installer or the NET installer.  That makes a
big difference, because the repos used by the NET installer are out of date.

If you want multiple NVRAM entries, I suggest you select the option to not
update NVRAM in the bootloader installation.  However, I'm not sure what that
would have done in your situation.

For me, boot speed is fine with 15.3.

If the BIOS does not recognize your NVME disk, then I would expect that you
would need "/boot" to be on a disk that the BIOS does recognize.  That's
because grub2 has to depend on BIOS services to load the kernels and to read
grub.cfg.