Yes, as has already been written. It is called a wireless uplink to the M. Set up as already written, do not do it via WLAN uplink: set up via LAN, see if everything works and then test the uplink first in general and then at the planned location. Remember that you must activate the general uplink capability in the controller software, that the AP connected via LAN must (only) have "uplink" activated and finally that the remote AP must allow the connection to another AP. This can be found in the respective settings. Otherwise, google the instructions.

Important: my experience shows that these APs from Ubiquiti are actually designed more for mesh, i.e. you need several instead of one that "blows" fully. This means that the connection often only works well over short distances in our buildings here. This applies to the wireless uplink as well as to client connections. (Balcony) glass doors and the usual reinforced concrete walls here are absolute poison for WLAN signals and even more so for 5GHz. In case of problems, I recommend running the M via 2.4 (strength "low" or max. "medium"), although I am not sure whether the wireless uplink always runs via 5GHz or also via 2.4 if you have deactivated all 5GHz.

Hello, this should actually work. I only have one AP AC-Pro and AP-AC-M MESH and after some initial difficulties it works. First configure the LAN cable so that wireless uplink is activated (there must also be a 5ghz network). Then a PoE line without data is sufficient for the power supply if the Ap-AC-M MESH is in the reception range of the AC-Pro or AC-LITE.