Leading up to the launch of Google Stadia, one of the on-demand streaming service's big selling points was streaming in 4K resolution. However, one of the complaints multiple critics had with Stadia upon launch was that Stadia wasn't delivering on that promise.
For example, Eurogamer's Digital Foundry editor Richard Leadbetter found that while the Chromecast Ultra TV dongle would output a Stadia stream of Destiny 2 in 4K resolution, it was actually upscaling the game running in a lower 1080p resolution. Leadbetter noted a similar issue for Red Dead Redemption 2, with the game apparently rendered at 1440p and then upscaled to 4K. Meanwhile, The Verge's Sean Hollister said Destiny 2 looked like 1080p on a TV through the Chromcast Ultra, and closer to 720p when playing through a Chrome web browser.

https://www.gamesindustry.biz/articl...ias-4k-support