This is a rematch, remember. Fluffy already holds a previous win over Allen in an LFA Middleweight Championship fight back in early 2018. The fight went all five rounds, but Fluffy was clearly the better man down the stretch. His cardio and scrambling ability allowed him to put a pace on that Brendan couldn't match going into the championship rounds. He won via 49-46, 49-46, and 50-45 UD.
Both men have gotten much better since then, but I don't know that the dynamic has changed significantly. Brendan still tends to slow down in grappling-heavy fights that go 3+ rounds. We've also seen that grinding chain-wrestlers with good cardio and good top control can give him fits even recently in the Malkoun bout. I think he's improved his wrestling a tad even after that Malkoun bout and his striking is more dangerous than ever... but I don't know that it will be enough. His BJJ is dangerous even when he's on bottom, but we've seen people be able to survive and escape bad positions against him as his level of competition has increased so I don't see him catching Hernandez with a sub unless Fluffy does something fairly ill-advised or is hurt first. I mean this is the same guy who spent five minutes getting smashed by Rodolfo Vieira and still managed to stay composed and safe on the mat before finding his opening.
However... this being a three-rounder does leave Brendan at least a few openings. He has a very underrated body kick that he uses to good effect in a lot of his fights and Fluffy's primary weakness above all else is that he gets badly hurt to the body in pretty much every fight. Hernandez does have serviceable boxing, but I think Allen is probably the superior striker. I think he should invest early in Fluffy's body and I don't think it would be a bad idea for him to mix in some takedown threats of his own. Anthony, despite his wrestling chops, actually has fairly porous TDD. He relies more on his scrambles than a good sprawl and Brendan's wrestling is... okay these days. In theory, he might be able to initiate the wrestling exchanges on his terms and focus on getting Fluffy to the mat and focusing on a boring, lockdown-style game on top (like he used against Imavov in Rd 1). If he chases subs and the like, it'll probably just give Anthony a chance to scramble and either wrestle up to his feet or reverse positions.
That said, I suspect Fluffy probably takes this. Likely by competitive Decision. I think Allen will win the first round before Hernandez comes on strong... but Brendan's live.