Might have figured it out. I just got the SD to reimage with the steam recovery OS.
The biggest difference is I UNZIPPED the .bzp steamdeck repair file before writing it to the external SD (USB probably works but it seems way quicker in my experience on an SD card). I also used balena etcher rather than Rufus to write the image to the SD card.
My WD 2tb nvme was not recognized in the boot menu, but was recognized in the recovery OS on the SD card.
Going through setup now and it looks like the wifi portion worked this time around (though it only worked on the 2.4ghz ssid). Steam says it’s installing, so I will update y’all a bit later!
If you take a look at my update you’ll see I was able to finally get the drive to be recognized in the recoveryos. I think the issue I had was some combination of taking the recoveryos file as-is from the site instead of extracting it and then also using balena etcher instead of Rufus.
Not sure whether Rufus or using the unzipped file was the issue. Try downloading the steam recoveryos .bz2 file and then extracting it on your computer. Then point balena etcher at the .img file that was extracted. Then boot into the detachable storage (SD card or USB) with the recoveryos and see if you can reimage from there. This is what finally worked for me, but ymmv. Good luck!