@skyfx64 that device what is connected to Ethernet port 4 has 100Mbps speed set. Can you check what is set for other router to use LAN speed?

On your router go Advanced > Network > Internet

Go down and look what is set:

Internet Port Negotiation Speed Setting

And change it drop down menu of your choice.

If it is computer than easy fix.

  @INTRASERVERNET all port 100 Mbps, i have 2 routers with the same type and firmware. 

  @skyfx64 if you show screenshot from your router config page then people will be more able to help you.

Hi  @skyfx64,

For your issue, please try suggestions below:
1. Connect a PC directly into your modem to verify if your modem is working well.
2. Login the web management interface of the Router, go to Advanced > Network > Internet > Internet Port Negotiation Speed Setting > set to "100Mbps Full Duplex".
3. Hard reset the router and configure it again. How to reset TP-Link router to factory defaults?

  @Joseph-TP Already try and still same situation, for internet port it can be 1000 Mbps but for LAN port stuck 100 Mbps, before firmware upgrade all ports can be 1000 Mbps.

  @INTRASERVERNET this is my config page 

  @skyfx64 On your AX73 looks ok, but what does it shows/set on other device?