It seems like a very cheap article. I doubt these claims of him training on low intensity and lack of attitude are true, it is nothing that can be seen on training footage, just the opposite, despite him being so far from playing most of the time.
The listing of the coaches that disregarded him is very dishonest - Valverde was never a question, Setien used him immediately and until he didn't pick the team himself anymore, Koeman obviously didn't trust him and maybe even hated him like some posters here seem to do, Sergi was interim for a few weeks and tried not to change too much.
Why Xavi doesn't trust Puig is a question I've already written about. It is true that all managers need to find a few players they trust for each position and focus on them, and also take into account the squad dynamics. Xavi has chosen Pedri, Gavi, Frenkie and Nico for these positions, and even though I agree with Iniesta Ultra that Puig should be even better than all of them, I can understand Xavis decision, it is an easy decision to make when taking over in mid-season. I believe Xavi thinks that Puig is a bit too ambitiously unpredictable from the middle of the pitch. I think it is a shame he cannot find another spot for him, like the LW Gavi position for example, or the false 9 one. Both because his immense talent ad excuisite class would be needed on the pitch, but also because him getting some minutes would increase his value when he is inevitably sold.
