Yes, it was only after grub that the drivers were loaded and the kernel presumably panicked or at least nothing was displayed. Not sure if that is what you mean by bricked the entire workstation. If something broke before the kernel is loaded I doubt it was because of the drivers. If you want to keep your current Debian installation alive you can try to chroot into it from a live usb. Sorry if this is completely obvious to you but I really don't know what to expect based on your description.

Having looked at your other comments and the post you linked I too am intimidated. It looks as though you have access to your boot menu and bios though. I don't know what the upsides of secure boot are but I never turned it on on my current desktop PC. Maybe disabling it could help?