Thanks for following up. I tried the bookworm netinstall and the PXE boot, but the install failed in the same way:
I used the netbot.tar.gz as well as the USB
b41d766e5389b4e35bac3a664da84822e0990439c9c4df933ddbaff6847a0009 ./netboot/netboot.tar.gz
I managed to get the PXE netboot to work using DHCPD and AFTPD. I modified the splash.png to be a black 640x480 PNG file and also updated grub.cfg to replace --- quiet with --debug.
I was able to boot into grub and then I issued the commands based on the "Expert install" menu entry:
linux /debian-installer/amd64/linux --- debug
initrd /debian-installer/amd64/initrd.gz
boot
After issuing boot, the installer hanged indefinitely with no output. Here's a 1m video of this after pressing Enter on boot:
Is there a way to get more verbose output to figure out what is hanging boot?
I also want to add that I tried an Ubuntu image and this booted properly: