Benetti started with ESPN on the national stage. Worked his way up to more CFB and CBB assignments, and as a backup MLB guy. ESPN let him work Olympic Baseball for NBC in 2021. Not something we will have to worry about until 2028. He also did Peacock games while still at ESPN before moving to Fox. He moved to Fox last year when ESPN reduced its baseball package, so instead of the occasional Monday game before, it is now a regular Saturday game as well as Saturday College Football. Basketball won't interfere, except maybe Spring Training.
It is pretty standard. Off the top of my head, the Orioles, Red Sox, Twins, Braves, Mariners, Phillies, Dodgers, Giants, and Brewers have a national broadcaster on their TV Play by Play. Giving Gania some reps on radio isn't the worst thing in the world. Dickerson is in his mid 60's, and I honestly don't know if Benetti's disability make it less likely he is able to broadcast into his elder ages.