I've been contributing to OSS projects for a few years now and all I can say is that it depends on the project.

I have a few open PRs to a small-ish project for about a year now. The maintainers haven't even looked at it. The PRs in question replace broken CI, fix bugs etc.

On the other hand, I have merged PRs to a large project that took the maintainers a few hours to review and merge. The PRs here are minor improvements.

My take is: do not give up. There is a random person in Nebraska that would appreciate your help, you just didn't find them yet.