Same issue here.
I've noticed that the bluetooth volume can go up to a level Samsung deems acceptable then any further volume increase is considered past the red line. In fact, the volume slider line does become red. Anything in the blue works great for streaming, anything in the red skips every 20-30 seconds for about a second or two.
As for the texts, I am experiencing the lag only when the texts are sent. If I send one and immediately I start typing another, the typing gets lagged and it won't be smooth until the previous text has already finished sending.