You’ve got the time limitations in college but the NFL isn’t over working their guys either and honestly stays close to that by design. They pay their players to study film and prepare on their own.
There are more games to prepare for in the NFL.. that is something of note. Certainly debatable. I also remember Urban Meyer saying that every week in the NFL was like game week preparing for Alabama. But that’s using a college model in the NFL. True NFL guys and lifers have it down to a science and don’t overwork themselves and it’s more efficient and data driven game prep.
Also in college you’re monitoring grades for your position group, attendance, are they going out at night, and talking to their family on a weekly basis.. basically babysitting 10-15 guys.
Someone who has coached at both levels, currently in the SEC, said he put in about 80 hours a week in-season in the NFL and had 6 weeks completely off work with no responsibilities. About 40 hours a week the rest of the year. In college he works about 100 hours a week in season (7 days a week 5am to 8pm) 70 hours a week the other 8 months, and had 4 days off in February and 3 days off in May. That was it.
Most entry level guys and position coaches in college are weeded out and totally burnt out in February (used to be February - probably both signing days now) and June with the camps, visit period, evaluation and offer period. You don’t make any money unless you work camps every day/weekend as a GA. Easily 120 hours a week if you’re doing what they want you to do and if you want consideration to move up.