8060 is (currently) the port used for gateway area network (GAN) communication.
8750 was used for redundancy in all 7.x versions of Ignition, but as of 8.0 all redundancy communication also goes over the gateway network - so that port is not needed.
6501 is used for Vision’s ‘local client fallback’ setting - the Gateway will attempt to bind to 6501, on the local interface, so that a Vision client running on the same machine can, in the event it loses its main gateway connection, seamlessly fall back to the local gateway. It’s more commonly used with Edge panel - and if you’re not using Vision at all, you can also safely ignore it.