You sound a lot like me when I first approached Ash a year ago, especially the part about being new to Elixir and worrying I'd just reproduce my prior MVC frustrations (Laravel in my case) in Phoenix.
I've been using Ash for about a year now and it's really hit the spot. Wishing you well on your journey!
I'm planning on trying ash at the weekend when I have time, but right now it's still a little nebulous to me. Have you found a boundary where you end up just being constrained and you're just back to normal phoenix dev?