Is your Apple Magic Mouse behaving strangely? Mine was juddery sideways and wouldn’t move vertically at all, though the scroll was ok. I tried switching it off, back on and reconnecting but that made no difference. The fix was rather surprising. Pick it up and gently but firmly thump in back down onto the desk. Considering that the only mechanical part is the click button this is a bit odd. We call it in the trade “The drop test” and is often works because it can reseat or jiggle connectors and socketed chips but I can’t see that that applies here. Anyway, try it and see.