Installing Debian 12 and morrownr's Realtek driver (2023-07-03 edit)

Due to deepening dissatisfaction with Canonical, I replaced my Ubuntu Studio installation with Debian 12 “bookworm” recently.

tl;dr:

1. My backups, including the driver source, were compressed with lzip for reasons, but I fell back on a previously-built rescue partition to get the system online.
2. I ended up with an improper grub installation, that couldn’t find /boot/grub/i386-pc/normal.mod. I rebooted the install media in rescue mode, got a shell in the environment, verified the disk structure with fdisk -l, and then ran grub-install /dev/___ to fix it. Replace the blank with your device, but beware: using the wrong device may make the OS on it unbootable.
3. The USB doesn’t work directly with apt-cdrom to install more packages offline. I “got the ISO back” from dd if=/dev/sdd of=./bookworm.iso bs=1M count=4096 status=progress conv=fsync (1M * 4096 = 4G total, which is big enough for the 3.7G bookworm image; you may need to adjust to suit), then made it available with mount -o loop,ro ~+/bookworm.iso /media/cdrom0 (the mount point is the target of /media/cdrom.)
4. Once finished, I found out the DVD had plzip, and if I’d searched for it (lzip), I could have used it (plzip). I didn’t actually need the rescue partition.
5. Once finished, I realized I hadn’t needed to dd the ISO back from the USB stick. The downloaded ISO was on my external drive all along, and I could have loop-mounted that.
6. [Added 2023-07-02]: Letting the swap partition get formatted gave it a new UUID. Ultimately, I would need to update the recovery partition’s /etc/fstab with the new UUID, and follow up with update-initramfs -u to get the recovery partition working smoothly again.

Full, detailed rambling with too much context (as usual) below.