Do you have projects that you personally admire? I assume you are choosing to donate to open source because you have an affinity for it. Personally I donate to political causes, particularly ones where I participate in/contribute to. Projects where I can get in the discord and talk to people, learn and really experience the practical side. I’m in a few Foss discords as well, so maybe joining some communities and getting to know people working with it, maybe learn to work with it yourself, will help and inform your decision.