Hi, every gamer will give you his own reply because that particular mouse will satisfy only their needs. You see, according to pro players the best mouse needs to have certain characteristics, which are important for playing. Such as comfort, flexibility of configuration, good sensor, anti-slip surface availability etc. Personally I simply adore Logitech G Pro Gaming FPS Mouse with Advanced the most because it contains all these factors. Plus it features an advanced optical sensor that handles precision, using hand movements to help inform what is happening on-screen. Nevertheless I recommend to have a look at this list https://csgopedia.com/best-mouse-models-for-playing-the-cs-go/ which is based on parameters and the preferences of pro players which were analyzed from the base of CS:GO pro players' setups. But you need to remember that first thing you need to choose is a comfort for your hand form
I am using Logitech G502 Proteus Spectrum to play Fortnite. It has 11 buttons, and I set walls, ramps, and floors respectively as thumb button 1, thumb button 2, and scroll wheel. This is a pretty decent mouse.
But of course, it depends on your personal preference. Some people prefer mice with fewer buttons, some prefer more. And it's also dependent upon the kind of game you play. The G502 series, for example, is pretty heavy, so it may not be suitable for people who play first person shooters.