Cool idea for a post, especially because of your unique perspective.
I see the two jobs as apples and potatoes. In the M, you’re managing people and in the bigs you’re managing players. Not that you’re not a player in the minors or a person in the majors, but that’s the focus.
In the M, you really have to support the individual and give them what they need to be successful in the league long term, and well after they fly away from your roost. The primary goal in the M isn’t necessarily to win this season, it’s for your players to retire after eight seasons in the V.
In the pro league, you gotta manage the team. Wins and losses matter. You might end up trading a friend and that’s the way she goes sometimes. Happy players in the big leagues are winning players (or players who know their GM has a vision for success).
Fun is relative, what’s rewarding is relative, and really, managing in either league will be fun and rewarding!