https://wccftech.com/youtube-on-android-now-lets-you-play-4k-video-on-devices-with-lower-res-display/

The YouTube app on Android has just received a new update to let you play videos at up to 4K resolution. All you need is a phone that has a 4K display, as well as a good internet connection, and you are good to go. However, it seems that Google has now opened up the unsupported video resolution option on many devices, which in theory, will allow people to play 4K videos on devices with a resolution lower than 4K.

According to a few posts on the YouTube subreddit, the YouTube app on Android now lets you play 4K videos even if you do not have a supported phone, considering how smartphones with 4K display are not available in abundance. A Reddit user, u/Liskowskyy, shared a screenshot that shows all the video resolution options up to 2160p regardless of your phone's resolution.