Prazeres generally gets matched up against small 155ers, he's beaten a couple of solid lightweights but overall most of his wins have been against small outclassed and outmuscled opponents.
Cummings isn't fantastic, but he's a big WW and an all around solid fighter. Despite being a ball of muscle, Prazeres shouldn't have the strength advantage that he has over his usual smaller opponents at 155 given Cummings being a big WW and having previously fought at 185. Cummings has a 7 inch reach advantage too so if Tractor can't get him down, he's likely going to be getting potshotted and missing a lot of what he throws in return. It could be a concern if Prazeres does get him down, but Cummings recently got his BJJ Black belt so it's no guarantee that Prazeres finishes him. If Prazeres isn't strong enough to take Cummings down and keep him there, I expect to see Zak controlling the fight on the feet and clinching to pin Prazeres up against the cage and land short shots to wrack up points.
I did just see a weigh in video of them both stood side by side though and Prazeres despite being a lot shorter is noticeably wider in the torso and shoulders than Cummings. He looks stronger there but I think Zak has that functional strength from fighting bigger guys constantly whereas Prazeres seems to force everything and get it through sheer muscle. If he struggles to take Cummings down and is made to work for takedowns it could be a case that he slows down more than he would at 155 as despite the lesser weight cut he'll be working those muscles more in fighting for position/takedowns.
If he comes out and takes Cummings down with ease though (which I guess isn't out of the realms of possibility, Yakolev and Coy both took him down in his last 2 fights), it gets very interesting and Prazeres could be a live dog.