I think I’d have a hard time picking out single projects to support. I sometimes do one-time donations to things I like (for example I donated to LocalSend one time when I discovered it and liked it a lot).
I have a regular donation to the Electronic Frontier Foundation though, which I feel sort of covers the same area in a more general sense.
It would be really hard to decide which open source projects would be deserving of such a foundation’s grant.
That said, if you want to support open source in a more general way, I would say you should donate to the Electronic Frontier Foundation (EFF). Cory Doctorow, the guy that invented the term “enshittification”, is part of EFF. I donate myself, it’s well worth it I think.
I’ve been very happy with typst. Works great and so much easier than LaTeX.