OP’s issue is he is in a dense apartment building with a lot of other hotspots competing for the same radio channels. WiFi 6 has a lot of tech to minimize the cross interference, but that will absolutely impact his performance and it will be nowhere near theoretical peak speeds. I used to have a corporate office WiFi network on WiFi 5 that would occasionally see a burst of noise that would basically offline our WiFi. No idea the source, but we were 1 floor away from rooftop antennas and could see a radar dome out the window. Never did figure out the cause.
Curious if power line Ethernet bridges would work in this case? I don’t know the current state, but it is supposed to be much improved from early iterations.
Another option is a WiFi bridge that outputs an Ethernet line, this lets you find an optimal place for the receiver, separate from the Apple TV. Dump that into an Ethernet switch and you can hardwire everything in the room