First put your phone in developer mode by tapping the build number fast 7 times, once it goes into developer option look for animation scale, there are three options, window, transition and animator scale, change them from the default 1 to 0.5 scale, and come back with the results
One thing people misunderstand about changing the animation scales is that this pretty much just your phone or pc FEEL fast, it doesn't really impact that much on performance, so don't take it for granted if you're into the intense stuff, it works for scrolling and responsiveness but it doesn't make your phone objectively faster
