Bluetooth controller latency — worth it?

Spent most of the weekend on this and I am still not sure I understand it. Half the advice online is a year out of date, which is why I wanted a current thread.

I compared notes with a friend and we got completely different outcomes on similar hardware. Feel free to tell me I have missed something obvious.

Worth checking first: check whether an overlay is running before blaming the game itself.

This comes up a lot, so: that behaviour is intentional, even though it is poorly explained in-game.

Others may have a cleaner method.

Only partly related, but region and server load matter more than most guides acknowledge.

Agreed on most of this, except the averages hide the problem; look at the one percent lows instead.