I have similar issues.
I bought SkyConnect mainly to get Zigbee as I bought 20 Aqara Zigbee window and door sensors.
My SkyConnect is connected to my HA Raspberry Pi4 with a 3m extension cable.
HA picked up SkyConnect immediately but adding devices has been very difficult. Even standing next to the SkyConnect dongle. However - I have somehow gotten 3 devices connected and they are visible in HA. None of these devices were paired on the first or second attempt but once they were paired they work very reliable (connection wise) and the response time is very quick.