You only had to watch the games around said period and look at the body language of Sane, a reluctance to work back for the ball when he’d lost it, a general exasperation when he didn’t receive the right pass and thus becoming disinterested in that phase of play. Things that do not sit well with Pep, or most fans I wouldn’t imagine.
Look Sane wanted away, for whatever reason it doesn’t really matter, homesick, lack of opportunities, whichever it was and that was evident on certain occasions when he took to the pitch. If he was still professional in training and during games, he’d get selected, bit like Garcia has been recently.