I don’t think they’re short of funds mate, I think the people evaluating the grant requests are short of time. That explains why they’d use nonsense metrics like GitHub - it becomes an easy no for them to move on to the next one if they can quickly look and put a cross in a box.
Geyserfund is closest to Opensats but you’d be self-fundraising.
Bitpac is nothing like it. That’s a model to bring in BTC investors for equity in a business.
Nostrocket is a hybrid where you could bring in investors but the funding mode is different.
Don’t be disheartened by Opensats refusal - seek other paths.