I don't use Air Pods or AAC, just taking a guess...
By chance did you already try the steps in the last comment of that link you posted? On my fresh install of Debian 13 I see that pipewire-audio-client-libraries, libspa-0.2-jack, pulseaudio-utils were not installed, makes me wonder if you somehow lost them or the other packages during your Debian upgrade (if that's possible)?
What I'd do is run
apt search pipewire-audio-client-libraries
apt search libspa-0.2-bluetooth
apt search libspa-0.2-jack
apt search pulseaudio-utils
For your system they should in theory display as something like [installed, automatic]. If any of those don't show as installed then run
apt install PACKAGE-NAME
Then restart the system and check if the aac codec is in /usr/lib/x86_64-linux-gnu/spa-0.2/bluez5 (and/or test your Air Pods and see how that goes).