Have you already considered working with/integrating with SPI [0] (Software In The Public Interest) that acts as legal and financial steward for many projects from large to small (e.g. Debian, NTPsec) ?
To give some context, if SPI were interested in receiving money for repositories associated with SPI, they would work with the developers to claim those projects on StackAid and associate their Stripe account. SPI's governance model can then decide how to allocate those funds.