Debian install on R630 "Unavailable" on boot

Hi Dell Community!

Disclaimer: I understand Linux/Debian is not officially supported. Alas I made an incorrect assumption when I purchased the server. If anyone strongly recommends that I return the servers and replace them at expense/effort due to issues I'll run into in the future (performance/compatibility/etc.) please feel free to let me know the general nature of such issues.

Goal:

Install and boot to the most recent Debian version on an 2TB NVMe drive installed w/in a PowerEdge R630.

Setup:

• Installing on a 2TB NVMe using a fresh USB non-free drive (created via `dd`); this drive is slated for containing the boot system.
• SSD drives for configuring the RAID10 (via `mdadm`) are in the mail.
• H330 PERC controller I'll just be passing through.
• 64GB SanDisk USB drive written over with Debian's official "non-free" install DVD image (firmware-9.8.0-amd64-DVD)
• BIOS 2.9.1 (flashed/upgraded it as part of troubleshooting steps)

Expecting:

1. Configure BIOS to UEFI w/o Secure Boot
2. Install Debian on the NVMe 2TB drive using the partitioning scheme the software recommends (EFT Boot partition, swap, tmp, home, var, etc.). This did not prompt me to install GRUB.
3. Reboot and load Debian.

Actual:

1. I completed steps 1 -> 2 successfully.
2. System fails to boot into Debian. It complains:
   `Booting from debian`
   `Boot Failed: debian`
   `No boot device available or Operating System detected.`
   `Please ensure a compatible bootable media is available.`
3. I hit F11 for `Boot Manager > One-shot UEFI Boot Menu` which displays (note the greyed-out and unselectable "debian" option):
       Select UEFI Boot Option
           debian
4. Both `Add Boot Option` and `Boot From File` display: `There are no filesystems available.`

I've tried the "Legacy" boot option (non-UEFI in setup) during which it prompted and I responded to install GRUB on the `/dev/nvme0n1` drive. That ended up not even recognizing an OS to boot.

If anyone has successfully installed Debian on an R630 and has any tips or tricks or if someone knows what I'm doing wrong here please help me, you're my only hope... and if your name is Luke I think your qualifications exceed the normal bounds here.

Thanks in advance.

John