For OpenTofu specifically, having DI for implementing state encryption would have been really nice. Of you look at the PR, a lot of code needed to be touched because the code was entirely procedural. Of course, one could just make a global variable, but that is all sorts of awful and makes the code really hard to test efficiently. But then again, this is a 300k line project, which in my opinion is way beyond what Go is really good for. ContainerSSH with 35k+ lines was already way too big.
I wish I had an answer to that, but I don't know. I only worked on projects of comparable size in Go, Java and PHP. Java was maybe the best for abstractions (big surprise), but it really doesn't lend itself to system-level stuff.
