The lawsuit is entirely premised upon the notion that the UFC is a monopsony, which the plaintiff lawyers are not going to be able to prove because it isn't one.
Bellators existence as a major buyer of services levels the MMA talent market to ensure competition is not imperfect. Bellator has deep enough pockets that they were able to retain Michael Chandler for his entire career up until this point, he obviously could have been signed by the UFC 6 years ago, but he stayed.... If the UFC had monopsonic power that reality would not exist.
This is a cash grab by disgruntled ex fighters, and while I 100% support them grabbing money from Dana & WME, don't fool yourselves into thinking there is legitimacy here. Theres a 0% chance this goes to any sort of legal trial, the plaintiff lawyers getting class action status just serves as an additional piece of leverage to force the UFC to settle because fighting the case would open them up to embarrassing public scrutiny and cost tens of millions of dollars.