Hi,
The wifi hardware present on the RPi3 have "limited capacities". I have 3 RPi3's in local network, only one using wifi connection (don't have lan cable at that place). I had some issues with built-in wifi and live TV, mostly stutters. I resolved by using an cheap USB-Wifi adaptor with external antenna. To disable the built-in wifi in "config.txt" add this line: dtoverlay=disable-wifi
That RPi3 with wifi connection I'm using now with latest LE10-nightly, not too often with TV, don't noticed any audio-video async or other issue (very-very-very seldom green artifacts on HD channels, probably because of new deinterlacing method, wasn't present with LE9 when I changed to USB-wifi).