I already explained you several times what you're doing wrong exactly: you're trying to compensate for a quirk of a particular media player by distorting colours, which becomes obvious in other media players.
An ability to store some data in superwhites in 8-bit codec because of YCbCr model has nothing to do with the 'greyish issue'. Shooting RAW does provide much higher dynamic range, but doesn't cause any 'greyish issue' either.
Any colour values above 1.0 are normally displayed as white. Or, probably more accurately, human eyes can't recognise colour values above 1.0.
There is no such thing as 'Adobe specification' for media players. There is colour management, which is intended to provide consistent colour reproduction across various devices. And it's up to you to decide whether to start learning it and therefore understand how your hardware, OS, monitor profile, various software etc. influence what you eventually see (and, consequently, which colour management tools to rely on, whereas an impact of which ones needs to be eliminated) or not.