He didn't make those 3 pounds because he felt big,strong, & still fast. He knew his conditioning was there too.
If he actually makes the weight its very realistic and plausible his power and stamina won't be the same.
One dude, who is huge for the weight made it but looked compromised. Couldn't take a punch. Flat. Weak legs.
The dude who didn't do the cut looked fresher in the last rounds & was literally toying with Devin.
He didn't like Derrick putting his ass in check when he was still mentally breaking down while winning. Or when Derrick waved off all the yes men trying to give Ryan advice in the corner in the last round like the fight was over.
Let's also not forgot Ryan has a history of parting with mutliple good trainers when they lay down the law & tell him the truth.