Reviewing code in PRs is not a no-effort action. If there are 3 people working in the project, and thousands of people submitting bugfixes, then no matter how useful those bugfixes might be, the 3 people will be totally overwhelmed by the sheer number of PRs.

There might be value in your bugfix, but maybe that value is not greater than the cost of reviewing and accepting it.

> Reviewing code fixes is strictly easier than coming up with them yourself.

This is completely false, for any sufficiently complex project. The fix might be a single line change, but the consequences might be far reaching.

> As a user-and-eveloper, why would I sink time into a project with such rules that put a barrier to improving my life with the software?

Please don't! You don't owe the project anything. The other side of that equation is that the project also doesn't owe you anything. As simple as.

Firefox and Chromium are running much larger teams, let alone the Linux kernel, that other people suggested as a model. Maybe they can afford accepting your contributions.