you're posted your query to the wrong community. Industrial Networking focuses on Cisco Industrail network portfolio. the CS3850 is not an Industrial Networking product.
Try "technology and support" -> "networking" -> "switching"
the Cable diagnostics output is concerning. its reporting a Short between pairs C & D.
seems a bit obvious to check the cable(s). try a different one?
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/17-2/command_...
well its up to every Cisco HW product team to determine if they want to support PTP or not. i do not know of list of company wide hardware supporting ptp.
you can try cisco feature navigator.
any Cisco network device which supports PTP can get time from a GMC. you can check datasheets to see if PTP is supported. if not listed in datasheet, then its not supported. and cannot get time from a GMC.
there's more. there are many different v...
