[jqpabc123]

sponsoring an open-source project so that it is well maintained?

Invalid assumption.

There is no guarantee of any kind with open source --- not for maintenance or direction or control or support or schedule or anything. Open source makes demands but offers no real promises in return.

If this is really a "critical" app and you need better control, I'd say you have no sensible/realistic option but to either built it yourself or at least maintain your own version of it. Lots of people have figured this out the hard way.