It wasn't just Epenesa's 40 that was bad. His agility scores were also poor and his jumps were average. On the whole, he tested out as a 15th percentile NFL athlete at DE.
I've said several times that the Combine does a terrible job of measuring strength and that is definitely his #1 asset, but he didn't do well at any of the metrics that have historically predicted success as an edge rusher (3 cone and broad jump). On top of that, he's not a clean fit inside at 6'5" 270, so you're looking at a man without a position.
20 years ago, he could have been a good 5 tech lining head-up on a tackle and two gapping, but DLs rush the passer 2/3rds of the time these days and I don't see how he has the explosiveness to win there. He projects as a Crawford-esque rusher off the edge where he simply doesn't have the speed to threaten tackles, and his power will be muted inside playing against guards. I would call him a Crawford type player, but Crawford's a better athlete.
Ultimately, I think Epenesa is a rotational guy only.