jellyfin is good but lots of bugs need help. "just being user" like me is not helping very much

It is not just about solving bugs, it is also about gaining mindshare. If a user comes to me and (politely) says "I want to use your product, but while issue X is not solved I will have to stay with your competitor", guess what will get prioritized in the backlog?

As a Jellyfin maintainer, I can confirm that these messages are never polite and are not prioritized.

What about the polite ones?

Or perhaps I should also add "reasonable" to the list of qualifiers? I can see that a larger project might be overflowing with well-meaning but mostly clueless people with unreasonable requests.

How are the ones who don't come to you contributing, though? You said merely using it is a huge contribution, but this example goes beyond just using it.

The one that is using without contributing any feedback is at the very least not using the competitor.

If someone asks them "what are you using to solve problem X" and the answer involves my product, it's my product that gets exposed to another user, who might be interested in contributing...