such a rule would be very difficult to make. let's say that there is a NGO that advocates for the rights of illegal immigrants. can a fundraiser donate more than $5,000 to that NGO? if not, I doubt that many NGOs would survive, so let's assume so. if that NGO wants to endorse Biden, are they allowed? if not, can they hint that people should vote against the candidate who wants to build a wall? If they are allowed to endorse Biden and they want to place an ad on TV, the production and placement could cost itself over $5,000
I think for the NGO to accept donations of greater than $5,000 from an individual, the NGO would have to agree not participate in political campaigning in any way.