I also like d a lot even if I did not use it that much (toolchain and getting things done problems mostly, besides not great platform support).

The metaprogramming of D is really impressive.

In fact I considered using Vibe.d for some backend: it has fibers. I love stackful coros in general (virtual threads in Java, for example). Way more than stackless for most uses.

But I am afraid that Vibe.d could not be flexible enough. With Java, Python, etc. I have more than enough for my needs right now.