Debian 10/Buster or higher would enable AppArmor by default.
However, any Debian based distro may decide to ship with AppArmor disabled instead.
A while back, Raspberry Pi OS's Linux kernel did not even have support for AppArmor and had to be recompiled by yourself if you wanted AppArmor support.
I think that has changed at some time with RPi OS's Buster release, but even with kernel support available, I'm unaware whether RPi OS comes with AppArmor installed and enabled by default.
And I fail to find any official statement from the RPi Foundation regarding AppArmor.
It should be easy enough to check on a given system, though:
sudo aa-enabled
sudo aa-status