I don’t know how many of you fall into this category of both using Google Slides and the Magic Mouse, but one of the frustrating things is that even a slight slide up/down gesture on the mouse will cause Google Slides to navigate to the next slide. Given that there is no actual scroll wheel and the sliding is done on the same surface that you click from, this slide navigation happens all the time.
There isn’t a fix from Google on this, but this Chrome extensions solves it: https://chrome.google.com/webstore/detail/stop-slide-scrolling-in-g/cmpmjbfhpecollipohbphhgbohleeeon/related
Maybe this will save you hours of frustration (spread out across several months!) haha.