Other source devices like an Apple TV 4K can easily go all the way up to the maximum HDMI 2.0b bandwidth of 17.82Gbps (3840x2160 60Hz 10-bit 4:2:2) without any interruptions. Weird thing is that 3840x2160 60Hz 8-bit 4:4:4 works flawlessly via the Yoga Slim 7 which amounts to 17.82Gbps. The problematic 3840x2160 60Hz 10-bit 4:2:0 only amounts to 11.14Gbps. So the problem does not really seem to be bandwidth related at first glance. Lower resolutions however also work flawlessly at 10-bit.
I tried the Lenovo VGA and AMD Adrenalin drivers. Both exhibit the same problem.