Regarding your AirPlay woes - have you checked the health (strength) and throughput of the wifi signal?
I have a lot of noisy stuff around my house so one thing I did was hardwire my AppleTV to be one less wifi device. That resolved all of my issues.
Additionally, I later ended up adding more Wifi APs to provide consistent throughput across the house. Previously I had "slow" zones. Not really dead zones, but annoyingly slow enough to force you to switch temporarily to 4G.
If you can't hardwire the device specifically, consider repositioning the WiFi AP closer, add/or add another AP if you are able to.
I’ve had terrible latency and connectivity issues with both chromecast and apple tv. Audio lagging, randomly deciding not to be discoverable, etc.
A cable always works