Realistically the prospect of living off open-source development on github is as likely as living on sales as a book author. It happens, but it doesn't happen easily or often.
If you run a super-popular project you might pickup a sponsor or two, but it seems that the odds are low.
He was using Patreon until the end of 2019, but has actually removed it since he already got so much corporate sponsors over the years (His platinum sponsors right now are Blizzard, Google, Nvidia, and Ubisoft... enough said.) And he wholeheartedly deserves all the money, since his UI library is just so monumentally important for anyone doing 3D graphics or gamedev.
https://calebporzio.com/i-just-hit-dollar-100000yr-on-github...
The ones that have a bit more sponsorships tend to offer some sort of priority support. But even that is very difficult.
I also maintain an open source project with 4k stars but we didn’t even bother with the sponsorship path and decided to monetize by charging for a hosted version.
For reference https://github.com/papercups-io/papercups
marcan is pretty close to full time for his asahi linux project. but he's also had a high profile (at least comparatively speaking) for ages now. it's pretty rare from what I can tell