There is also the solution of: No merge requests, just feature wishes and bug reports. All code is written solely by the maintainers (with the help of LLMs).
Add a mechanism to donate tokens towards the maintainers' LLMs for a particular ticket and this whole class of problems will be resolved all at once.
I believe that SQLite is like this. All code is internally written. Yep, also very reasonable. Amounts to how much external input you want, I suppose.