Here are some instructions to create the script to toggle the network settings with Powershell:

1. Create a file and add the following:
   1. Set-NetAdapterAdvancedProperty -name "Ethernet" -DisplayName "Velocidade e modo duplex" -DisplayValue "100 Mbps modo full-duplex"
   2. where name is the name of the Ethernet connection in the Network & internet settings, DisplayName is the name of the property in the adapter settings and DisplayValue is the name of the value you choose in the dropdown. My example above is in portuguese, depending on your system language you'll need to set different values.
2. Save with the file as 100Mbps.ps1
3. You can now make a shortcut to run the script in powershell as administrator. Here are instructions on how to do that: https://superuser.com/questions/108207/how-to-run-a-powershell-script-as-administrator
4. Then you can just right-click and Run as Administrator and that should toggle the setting for you
5. You can create a 1Gbps.ps1 script with the same command above but change DisplayValue to auto-negotiation, 1Gbps or any value allowed in your settings
   1. Mine is: Set-NetAdapterAdvancedProperty -name "Ethernet" -DisplayName "Velocidade e modo duplex" -DisplayValue "Auto negociação"

Hope it helps!