Don't really have the stats in front of me to back it up, but the Rams run almost no RPO's.
Go look at how much zone runs the chiefs, eagles, packers, etc. ran.
My guess is Nagy didn't just change up the blocking scheme just because. He changed it because it didn't fit what he wanted to do with all the moving parts in his offense.
One thing people also don't seem to get, is that Jordan Howard was NEVER a great runningback. I guess Windy gets it. JHow is a good back, but he lacks any kind of explosion or playmaking ability. He can't cut on a dime, has no real finesse in his run game, lacks acceleration or top end speed, and is below average in the pass game at best.
Howards ONLY elite trait is his vision, which is why he fits a zone scheme because he can wait for the hole to develop and is great at reading it and making one cut to hit the hole. Issue is, even in his first two years he'd hit the hole and get to the second level untouched just to go down.
The answer isn't to switch up Nagy's scheme towards Howards skillset. Why do that when he will be gone in a year? The answer now is to draft his replacement in the mid rounds, who is a better fit, and hope for the best.