One thing that's important to understand is that this is going to be a non-starter for a FOSS project that isn't a 501c3, for most companies, for legal reasons. Charitable giving to 501c3s is defensible spending because of the impact on taxes. (Yay Crapitalism!)
You'd probably have more success onboarding them as a contractor doing "implementation support".
Also, imo big projects like Linux and postgres are doing fine, and it's the small tool creators that need support.