> auto-formatters messing with line lengths is a source of significant annoyance.

Unless they have been a thing since the start of a project; existing code should never be affected by formatters, that's unnecessary churn. If a formatter is introduced later on in a project (or a formatting rule changed), it should be applied to all code in one go and no new code accepted if it hasn't passed through the formatter.

I think nobody should have to think about code formatting, and no diff should contain "just" formatting changes unless there's also an updated formatting rule in there. But also, you should be able to escape the automatic formatting if there is a specific use case for it, like the data table mentioned earlier.