I use a vertical mouse for work. The ergonomic hand position is more natural and reliefs the wrist. On top of that I noticed that horizontal mouse movement (wich is the most important movement in a Shooter Game) should be more precise too. At least in my perception. That leads me to the following questions:

Are there any empirical values in that regard, wether it is better or not in competetive manner? Maybe flicking is better but micro corrections are worse.

Is there any Pro that uses a vertical mouse?

Do you know a good vertical gaming mouse where you can set the exact DPI Value? I have a Logitech one where its not applicable.

Maybe we miss out on the best equipment for better aim and better wrist health without a good reason.