Hello,
Yes, Miracast hardware does support 4K at 60z but depends on the device. The 4K 60hz standard was updated in 2017, so you should look for devices that are Miracast hardware in version 2.1. This also includes that the transmiting medium such as HDMI cable is good enough to support the transmission. For example needs a HDMI 2.0 certified cable, and to be connected for the ARC connector of the display.
Regarding the Dolby Atmos, it is also supported by Miracast hardware devices, but you will need a external Dolby Atmos decoder to convert the digital signal into the analog realm (speakers)
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