If you're in the market for one, check Marketplace, Craigslist, eBay, etc for used Xbox One X or PS4 Pro One S consoles, they've gotten pretty cheap and play UHD blu-rays. You can even get media remotes for them and have almost the same experience as a regular player. If you already have one of these or an Xbox Series X or PS5 disk edition, congrats! You've got a 4K blu-ray player.

Edited correction thanks to SolarPunker