> If the goal is to fund full-time development of something and they don’t know if they are going to get the funding for seven months

In my experience, that's not the goal most FOSS projects have in mind from day 1. You might be working somewhere else, yet still release FOSS software and if it something in particular gets traction and makes sense to spend longer time on, you might start considering trying to be funded for full-time in some way.

But unless you have some following/funding from earlier, I don't think people jump feet first into FOSS like that, expecting "full-time employment" pay working on their project, but starts with something with smaller sources of income, like Open Collective or GitHub Sponsors/