Who manages Xfinity community internet

I recently moved into an apartment complex that I found out has Xfinity community internet. Initially during tours I was told that I would have a normal setup with a dedicated modem but the leasing didn’t understand the network. They told me I could still use my own router and equipment.

When I moved in the apartment instead has one Ethernet line in and two preset APs providing Xfinity service on a preset up private wifi network. The Ethernet line in does provide internet however I am unable to attach my own router to it as the router does not get an internet connection. The Ethernet is also not on the same  network as the private WiFi as I cannot see devices that are hardwired when on WiFi. When I connect to the hardwire and look for devices I am able to see devices that belong to my neighbors.

Additionally, my Internet speeds seem to have dropped as more people move into the building. When I was one of the first moving in I received closer to the listed speed for my account but as more people move in it has dropped below 10mbps download.
Because this is an Xfinity managed community internet, who would address these network concerns Xfinity or the Apartment Complex?