The temperature monitoring and throttling feature is very conservative. If you can afford a few extra minutes of charge-time then let the throttling happen as designed otherwise use the menu or WiFi to disable the feature.
The idle temperature will be about 2 - 5C over ambient, there is very little that can be done here as a station is only using about 1.5w with WiFi running.
During a charge session temperature rise is dependent on current. Reducing resistance will reduce heat, the largest factor is the wiring gauge. Thicker wires will reduce resistance/heat. Improving the connections to the relay may help but should not be a factor unless the connection is loose.