It looks like I’m the odd person out: I cut my potatoes before boiling and use a KitchenAid stand mixer for the mashing. My mashed taters are usually soft/fluffy/yummy.
For mashing, less is more. If you know this going in, there’s no harm to using a stand mixer.
Put your desire amount of butter in the bottom of the stand mixer. Peel, slice and add to cold water. Salt if desired. Boil until they cleve cleanly with a fork. Drain, dump on butter, let rest a few minutes to soften the butter. Mix and add milk as necessary. A little minced rosemary with the potatoes when they go into the stand mixer is 👌