It’s probably because of drivers? I’ve seen some people on a dutch forum that have it down to about 6/7W, mostly the issue is power modes on the realtek model. I’ve tried to figure it out but am just not great at linux.
What OS are you running?
This driver should help with power consumption. and then you can use following script if ASPM doesn’t work (please read the script and use responsibly)
You can use this script for seeing what the aspm status is on your computer. lspci -vv | awk '/ASPM/{print $0}' RS= | grep --color -P '(^[a-z0-9:.]+|ASPM )'