This comes up every now and again. The path to Official is that a few big customers, many small customers, or very many self-hosters are using it. This seems improbable in the near term.
It took a talented developer several months to get an already-working subscriptions plugin into shape, so it’s a pretty big job. But you might be able to scope things back a bit.
I’d be somewhat interested to hear more about what you want to do.