Note that the grandparent didn't say "luxury" anywhere.
If you're good with 4 stars you could probably get there with a little internet sleuthing.
Casinos running specials trying to attract gamblers during the off season is probably the best bet. Or low population areas like the midwest.
https://www.wonderslist.com/15-cheapest-5-star-hotels-usa/
https://www.gobankingrates.com/saving-money/hotels/states-wi...