Installed on mine through the Windows MSI updater and am seeing the same issues with Retimers23 as others. The left rear port works for charging but not for Thunderbolt, the left front port does not work at all, right side ports appear to be fine.
Tried the 2 minutes power off and 30 second power button hold-down and neither one appeared to resolve the problem with Retimers23. At some point the message in Device Manager changed from “your computer needs to restart to install the update” to “the device cannot start” and it no longer offers me a reboot prompt. Not sure if I should uninstall and reinstall the updater package to try to get it to go again or not.
UPDATE: I uninstalled the errored Retimers 23 device, reinstalled the MSI, rebooted, and this time the firmware update took. Computers!