I'm not a maintainer, but if it's a showstopper, then it seems like you should just get a developer to write a patch no? You could probably ask the maintainer whether they can help do this, but if not, just ask for (potentially paid) assistance so that they can help your developer get up to speed on how to fix it.

In the worst case you would just have a separate fork until the patch is accepted upstream, assuming that happens at some point.