Does the USB-C Digital AV Multiport Adapter transmit 4K 60Hz signal from M1 MBP?
Solution 1:
I just tried plugging a 4K monitor into my M1 MBP using that adapter, and it only gave me options up to 30Hz at 4K.
I also didn't see any M1 Macs listed in the 60Hz list. So I suspect that all the M1 Macs will only run at 30Hz using a 4K screen on that adapter.
Solution 2:
Yes, it can, but you may have the old version of the Apple Digital AV adaptor. You need to make sure the adapter version is A2XXX, not A1XXX, since Apple updated that adapter in 2019 to support HDMI 2.0.
I have an M1 MacBook Pro and I can confirm the updated version of the Apple Digital AV adaptor does support a 4K 60hz HDMI connection.
Solution 3:
I can also confirm that 4k@60Hz is supported on a MacBook Pro (13-inch, M1, 2020, two thunderbolt ports) running macOS 12.0.1 (21A559), with the USB-C Digital AV Multiport Adapter A2119.
This is despite what the linked page says.