Sounds like it’s perfectly suited for indie game development where everything plus the kitchen sink is a must and the more customizable the better.
That said, in principle one could imagine a version of Unity that used D instead of C#, and I think that would be a pretty neat combination.
You would have to weight this choice against existing engines like Unity/Unreal/Godot vs custom. I released a game with custom engine in D once and what really mattered was that there was no market fit (and no sales). Choosing engine vs custom is a question that only exists if people materialize to play your game ; a lot of successful game shops are prototype-heavy or at least advise that strategy.