有無試埋safe mode?
我就咁聽懷疑有3rd party軟硬件問題,例如轉custom resolution嗰d
或者硬件係DisplayLink dock會disable HDCP等等
呢堆野如果有裝某kernel extension響部Mac,要入safe mode先會暫時disable唔load
講真任何地方都播唔到片一定係大問題,不過我會起碼pinpoint到有某software環境下無事,先去斷定硬件有問題,因為硬件有事會好難想像淨播片唔得而其他draw screen得
btw你亦應該試埋插外置mon / TV,甚至AirPlay出去,同埋remote screen sharing入嚟,總之試吓搵到一個唔同途徑係播到片;
如果真係全部唔得都幾出奇吓