For those who own a Mac that has been released since 2018 and has the T2 security chip, will be able to stream 4K content from Netflix. When Apple released macOS Big Sur later this year, Mac users finally got the 4K streaming feature in HDR from Netflix. However, it was not just the 4K supported screen that made it possible, but a lot more. In a support document from Apple, it was found that the T2 Security chip in the Mac was the factor that allowed 4K streaming on the device.
This would actually mean that only the latest Macs released after 2018 and with the T2 security chip were able to play UHD content from Netflix. The list of devices with the T2 Security chip is as follows, Macs: 2018 or later MacBook Pro, 2018 or later MacBook Air, 2018 Mac mini, 2019 Mac Pro, iMac Pro, and 2020 iMac. The 4K streaming ability is connected with the T2 chip’s ability to process HEVC encoded videos. Apple also states that the coprocessor can transcode HEVC video up to twice as fast as its previous generation T1 chip.
Therefore if Netflix is using HEVC then the requirement of the T2 security chip for displaying 4K content from Netflix is explained. If you do not have the Mac which has the same T2 security then you will not be able to stream the 4K content in any way from Netflix. However, you can stream 4K content through the Safari browser as other browsers limit the play to 720p.