Let me start by saying that both are formidable weapons to have un your arsenal. A lot of folkstyle wrestlers have succeeded in the UFC and are actual champs like Usman.
That being said, the propaganda keeps repeating that folkstyle is the most suited to MMA competition because of the ride, because if this and that... People like Chael Sonnen, Ben Askren and such can't shut up about how folkstyle is tailor made for mma, with askren going as far as calling it "the most superior martial arts in existence" (LOL)
But in fact, is it more effective than freestyle wrestling in the context of mma ? If we look at statistic we see that no. The amount of ncaa/college wrestlers is HUGE in the UFC. I think i could name almost a hundred that have wrestled folkstyle in college just by memory. Compared to that, freestyle wrestlers are but a fraction of the wrestlers on the roster. And yet they are much more dominant. All those dagestanis/chechens with wrestling background make it
work, both defensively and offensively..
And most of the time when a folkstyle wrestlers fights a freestyle one he loses the wrestling battle. Look at Khabib vs Abel Trujillo, Pat Healy & Gaethje, Makhachev vs Nick Lentz, Askarov vs Benavidez...
The best wrestlers, the most dominant ones, have been freestyle/olympic style wrestlers. Just look at Khabib, GSP & Cormier. Maybe the 3 best wrestlers in MMA history. And all wrestled freestyle (Cormier did also folkstyle i give it to you).
TDLR: Folkstyle wrestling is good for mma but way too overrated, it's not the best wrestling style for mma, freestyle wrestling is, and freestyle beats folkstyle almost each time they fight
EDIT : A very good point made by our friend
@Simple'Slam