I came across this article on the ATP site and thought how Shapovalov comes across as a mature and decent young guy - clearly he was mortified by what happened in the DC and seems to have vowed to grow and learn from it. He is clearly talented, hope he moves on to rise up the rankings.
Good luck to him, he's is obviously being well managed and ATP looking after one of its stars of the future by giving him a platform on which he can write something sensible. Being so successful so young comes with it the unenviable scenario of growing up in public.
A similar incident happened in the final of the High School boys at Ojai with a player blindly hitting a ball into nothing in particular in rage, the umpire did nothing. It merited a warning if being lenient a disqualification more appropriate but then no match for the fans to watch, the final is tarnished etc... disqualification would hopefully have been an experience the player concerned would have to grow from as it was he learnt nothing.
He did act like an egotistical prat at the end of the match with Broady and his "handshake" was pathetic. In fairness I have no idea what happened after the cameras stopped rolling and maybe he calmed down and apologized to Liam after they left the court.
Liam posted it on twitter, I haven't seen Liam involved in any argie bargie apart from that and my impression is is that he is willing to stand his ground if he feels there has been any gamesmanship or rudeness around the formalities of the game.
Denis I feel has something to work on which will be hard given his profile and likely documentation through social media of any infraction.