I am one of those who say frozen mash is good. At least, Auntie Bessie's is good and so is Tesco's own brand. I haven't tried any others. It is useful to have a bag in the feezer - they are in small lumps, so you can take out as many as you need at a time, put them in the microwave with a little water and a knob of butter for a few minutes and give them a stir.
Same with a bag of potato croquettes, they take 15 minutes or so in the oven or air-fryer and are crisp outside and soft inside.
Potato Pops are Malteser-size balls of potato in batter, better for nibbles than a meal, but they go down well with children.