RHEL8 dracut initramfs switch-root hanging on one machine and not others

I have a 2TB external SSD connected to a server. Using the server, I booted into the RHEL8 installer and successfully installed onto the external drive, however during the post-install reboot (and all reboot attempts after) the boot hangs at the switch-root step. Obviously the drive is recognized by the system and is able to provide the bootloader / initramfs, but dracut/systemd seems to just hit a hard stop when switching to /sysroot using the slash partition on the drive (non-llvm ext4 formatted). The interesting thing is several machines (laptops, desktops) will successfully boot from the drive into the OS, indicating the server chipset/usb bus is the cause. Unfortunately, I am stuck with the server (a Gigabyte... didn't realize they made more than boards) and the external drive (a Kanguru UltraLock SSD). Kanguru claims there are no drivers required for their drive, which makes sense. Also, I have not attempted to update/flash the UEFI on the server. I've avoided it for fear of making things worse. I did try adding a short delay in a pre-mount-hooked dracut script within the initramfs, thinking it might be a race condition of some sort, but it had no effect. That script also does an ls /dev/disk/by-uuid which shows the drives and partitions as they should be (i.e. the root=UUID:.. in the kernelopts matches the partition in the list). Anything obvious I'm missing? Update: I realized that I actually used a PXE kickstart to install the OS because I was unable to boot into the RHEL8 installer using my thumbdrive USB stick. Initially I thought the issue was my stick (old USB2 SanDisk), so I switched to my PXE server on my laptop. I just tested a theory now and was able to boot into System Rescue (CD) on that same USB stick that did not work with the RHEL8 installer. System Rescue CD uses the typical embedded busybox boot approach, which seems to point to a dracut issue in RHEL with regard to the server's hardware or USB connections? Thanks in advance!