I think the term toxic players is not the right one to describe the issue in the squad.
I think the problem stretches to the fact that we have camps in the squad (french-connection vs academy players) and those camps got stronger with the sacking of Mourinho as it was evident the players had the final say in his tenure (which I am happy about how it ended because he was a prick and a fraud)
I think his persistence with Lukaku up front despite being off-form and Matic in midfield caused a huge split within the squad. On one hand you have those players guaranteed to start while others like Pogba and Martial had to put in a 10/10 shift to play despite being the ones who would actually change the game.
Looking back at our run of games under Ole, we were in the driving seat, players who felt underappreciated started playing well, till the second tie of the PSG game.
After winning that game, you would have expected the players who actually won it to feature in the next games, but that was not the case, instead, the favored academy players got straight back in and the result was a huge drop in form (lost to arsenal and wolves in two competitions). The idea to persist with Rashford despite being so bad post-PSG and the idea to bring Lingard back in the lineup despite being useless and still not recovered 100% from injury clearly reignited the problems within the squad.
If I were Pogba and I look at this crop of average players surrounding me, if I am De Gea and I look at the average defenders supposed to lead the backline, there isn't much to discuss. I mean Young/Jones get contract extensions for what? Both are most likely to leave because it is evident that despite bringing in a new manager, favoring average english players in our squad has not really changed.
It is not about toxic players but rather poor man-management skills by the previous manager and the current one and of course the board being so lenient with players by giving them ridiculous wages, and those contract renewals wouldn't have been happened if they were not approved by the manager.
Ole should cut his affiliation non-sense with the likes of Smalling/Jones/Lingard/Rashford/Young because in all honesty those are the poorest english players from the current england lineup.