I think open-source leaders who want sustainable resourcing should focus on building obvious paths for people who find ongoing value in their project to contribute. That to me is the best return-on-investment.
If it's a library, make it easy for developers to contribute code.
If it's an app, make it easy for individuals/businesses who value it to pay (e.g., cloud hosting).
I gave a talk about this at the launch of WHO's Open Source Program Office[1].
So I thought that having an open source project in DPGA would be really great but it seems that everything that glitters isn't gold like how you mention support requests etc.
I have a question tho, What are the best foundations or labels (like DGPA) that an open source software can qualify for which might give it more exposure and funding
Personally I am starting to believe it might be NLNET (https://nlnet.nl/) but what are your thoughts on it?