That's not easy though, especially not for large and old code bases. As an outsider doing occasional bugfixes when I spot issues in an open-source project, I don't have the time to dig into how exactly I need to set up my computer to even have a minimum viable build setup, adhere to each project's different code standards, deal with the bullshit called "Contributor License Agreement" and associated paperwork, or wrap my head around how this specific project does testing and pipelines.
What I can and will do however is write a bug ticket that says what I think the issue is, where my closest suspicion is that causes the issue, and provide either a reproduction or a bugfix patch. Dealing with the remainder of the bureaucracy however is what I do not see as my responsibility.