When installing a Kali Linux using the netinst ISO (note that the following issue does not occur with the "standard" ISO) and choosing KDE Plasma as the desktop environment, the resulting Kali installation only comes up with a TTY login. The issue can be fixed with a simple sudo systemctl enable sddm --now.

The resulting install does not have sddm enabled. Neither is the display-manager.service symlink created. To me this strongly suggests sddm is simply never enabled, but I can't tell why that is the case.
The issue only occurs with the netinst ISO and has been introduced within the last 2 months (old VMs from before then didn't have the issue). Unfortunately I do not have enough old VMs to further narrow down the time window. There is a chance it has something to do with the bump to Plasma 6.6, which introduces Plasma Login Manager (see: https://fedoraproject.org/wiki/Changes/PlasmaLoginManager). Though to my knowledge sddm should remain the default and this should not cause any issues.

Please do let me know if you need any further info.