The problem is very simple, when I use wi-fi I get 100mbps on speedtest.net
When I use ethernet cable, I get 30mbps.
I tried different cables and PCs and got the same result.
If change the speed here https://i.imgur.com/KJFX6HP.jpg to 1Gbit, the ethernet ports stop working.
If I change it to 100mb full duplex, I still get 30mbps max.