A trick I use is to play at least two games on Freshmen for all underclassmen who I want to come out in the draft. Preferably before week 8/9 so that they can become eligible for the awards.
Then I'll save the Franchise under a new save file before the Bowl Game week. Advance through to the offseason a few times to see which players are/aren't declaring for the draft but don't save the dynasty. Then go back to the old dynasty save file and play the Bowl Game for any players who you didn't see leaving early.
You'll only need a quarter or so to rack up insane stats on Freshman, so super simming the rest saves you 20-30 minutes.
For defensive linemen, play on Varsity/All-American as the opposing team and run the QB into the defensive player so they can rack up sacks.
For cornerbacks, play on Heisman as the opposing team and throw go routes and deep outs at the CB whenever they are in man coverage so they can get INTs.
For linebackers, play as their team on Freshman, call LB blitzes, and use a DT/DE to manually occupy the blocker who is in their gap. They will get at least 2 sacks per game and a ton of tackles for loss on run plays.