Finally start contributing to the FOSS world. I’ve used stuff like express and vscode for years, but am yet to open an issue or submit a pr to any major FOSS repo

It doesn't need to be a major repo. It doesn't even need to be a major change.

I've never met a maintainer that will close or get upset about a typo-fix PR. Start there if you're particularly nervous.

(I maintain tons of OSS, including large repos, for context)