As per my comments, there are no "official Debian images for the raspberry pi". The site you found, raspi.debian.net, is not part of the official Debian site, debian.org, and the notice in the page footers makes this explicit:
This site is not an official Debian project. While the maintainer (Gunnar Wolf) is a Debian Developer, content herein provided should be considered unofficial.
This does not mean there is anything wrong with the images, etc.,1 but it does simplify your question, because there are no Debian policies here to question or consult. There's just Gunnar Wolf's website, and since he has not updated it for the Pi 5, it's pretty unlikely that he has updated the images, and the "Download tested images" page makes that pretty clear.
However, since he autogenerates a set of images nightly, depending on how those are made, it is not impossible for them to include the necessary updates -- all that needs to be done is that the boot partition and kernel modules be copied from the Raspberry Pi git repo. That boot partition, is (minus some text files) the same as the one used with RpiOS, and suitable for all models.
Unfortunately though, the nightly build images from Gunnar are not. I downloaded the bookworm image for the Pi 4 and this is what's in the boot partition:
bcm2711-rpi-400.dtb*
bcm2711-rpi-4-b.dtb*
bcm2711-rpi-cm4-io.dtb*
bcm2837-rpi-3-a-plus.dtb*
bcm2837-rpi-3-b.dtb*
bcm2837-rpi-3-b-plus.dtb*
bcm2837-rpi-cm3-io3.dtb*
bcm2837-rpi-zero-2-w.dtb*
bootcode.bin*
cmdline.txt*
config.txt*
fixup4cd.dat*
fixup4.dat*
fixup4db.dat*
fixup4x.dat*
fixup_cd.dat*
fixup.dat*
fixup_db.dat*
fixup_x.dat*
initrd.img-6.1.0-16-arm64*
start4cd.elf*
start4db.elf*
start4.elf*
start4x.elf*
start_cd.elf*
start_db.elf*
start.elf*
start_x.elf*
sysconf.txt*
vmlinuz-6.1.0-16-arm64*
There's only one kernel and firmware set there, and they are explicitly for the Pi 4. Unless the Pi 5 can use them (which is unlikely), you are out of luck until Gunnar gets a Pi 5.
- It is referred to by the "Debian Raspberry Pi Maintainers" and in the Debian wiki,
debian.net
subdomain, but "debian.net" does not really exist beyond that; Debian's real site is debian.**org**. If you look for "raspberry pi" using the search on the real site, a lot of stuff comes up, but none of it is a link to raspi.debian.net. Also, the fact that this is really just one person doing his/her own thing is spelled in the first question of the FAQ...