Yes, indeed. I just checked that myself as well. Newer experimental Armbian (v24, edge, current) contains the corresponding header and image deb files for the RaspberryPi5. However, not the latest stable version. Furthermore, the stable version for the RaspberryPi4 seems to be affected as well. Also there I can't install the corresponding linux-headers package patching the currently running kernel version. See:
# apt install linux-headers-$(uname -r)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
E: Unable to locate package linux-headers-6.1.68-current-bcm2711
E: Couldn't find any package by glob 'linux-headers-6.1.68-current-bcm2711'
And the same applies for the linux-image package:
# apt reinstall linux-image-current-bcm2711
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Reinstallation of linux-image-current-bcm2711 is not possible, it cannot be downloaded.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Hopefully some Armbian dev can fix that ASAP so that the corresponding linux-headers and linux-image packages for the RaspberryPi5 and RaspberryPi4 are available in the apt repositories.