We did evaluate pulumi. Our experience was that it basically gives you alternative, more error prone way to create terraform resource graph. Also while they claim to support python, it definitelly feels like second class citizen, it's not very idiomatic (more like almost-literal rewrite from the typescript).

So for time being we are sticking with terragrun&terraform combo.

But the concept of pulumi looks interesting and we will likely re-evaluate in a year or so to see if it has moved in the right direction.