comments:
I just emerged from the rabbit hole on a similar issue with an Innocn 40C1U 5K2K 100Hz monitor. I wanted to use the monitor’s HDMI 2.1 input through a TB4 dock (TB5 in the future). It turns out USB-C to HDMI 2.1 adapters on Mac is complicated. I found a working solution in a MacRumors forum post, below. The very specific Cable Matters adapter that worked for me also below. Note you need a Windows PC to flash the firmware. None of my TB4 docks support HDMI 2.1 which is why I went down the USB-C adapter path. From this thread it appears the TS5+ also does not fully support HDMI 2.1, which is disappointing. Can this be addressed with a future firmware update? I see a lot of issues about this dock here but at least the support is responsive and firmware development has continued. https://forums.macrumors.com/threads/dp-usb-c-thunderbolt-to-hdmi-2-1-4k-120hz-rgb4-4-4-10b-hdr-with-apple-silicon-m1-m5-now-possible.2381664/ https://a.co/d/085Oxp2xNote there’s an almost identical adapter from CM that says it’s specifically for the Mac without needing a firmware update. I bought it as well and it only supports 4K 60Hz.