Yes.

I personally prefer having IaC in the same repo as the code. Any changes to the code OR the IaC uses the git flow as per normal and requires a PR. When the PR is merged to develop its pushed to QA environments automatically - therefore updating infrastructure with the updated IaC.

We update deployment configuration separately (because why would we include anything environment-specific in the repo?), this never presents any major issues although sometimes I guess you'd need to update the config just at the same time as merging the code PR which is slightly inconvenient and is somewhat OCD triggering, but its a productive setup so I don't mind.