I have to warn you about something. Look at a bag of Red Bliss or a pile of pretty Fingerling potatoes. They look perfect. They are liars.
These are waxy potatoes. They have a low starch content and hold their shape when boiled. This is fantastic for potato salad or roasting, but a disaster for mashing.
If you try to mash them, you will not get cream or fluff. You will get a bowl of sad, slick, dense lumps that resemble cold Play-Doh. The texture is gummy and never absorbs fat properly. Step away from the red potatoes. They are not for this job.