Peel and cut potatoes into quarters lengthwise. Remove any spots, lumps, or knots. Wash until the water runs clear.
Place potatoes in a large pot (6-quart) and cover with cold water by an inch. Add some salt. Bring to a boil and reduce heat to medium-low. Simmer until fork-tender, for about 15-20 minutes.
Drain and add the hot milk, hot cream, butter, garlic powder, onion powder, salt, pepper, Ranch powder, and sour cream to the cooked potatoes.
Mash the potatoes with a potato masher until smooth, adding a little extra milk or cream if needed. Use electric beaters to beat further until smooth and fluffy. Be careful NOT to overbeat.
Add in the cheddar cheese and chopped bacon. Stir to combine.
Serve hot, garnished with green onions, chopped bacon, shredded cheese, and butter.
