Use CAT6a. You’ll have no issues.
30’ of 6a is less than fifty bucks from BlueJean
Ethernet Wiring
I prefer to use a hard connection as opposed to using Wi-Fi. Our basement is finished off, so my only access point requires me to run the Ethernet cable through approximately 25' of HVAC ducts. Is this okay? The cable would be inserted into the duct about 15' away from the furnace plenum. Thank you.