Using a Powershell script.
if( (Get-NetAdapter -Name "WiFi").Status -eq "Disabled"){
Disable-NetAdapter -Name "Ethernet"
Enable-NetAdapter -Name "Wifi"
"Wifi enabled, Ethernet disabled"
}else{
Disable-NetAdapter -Name "Wifi"
Enable-NetAdapter -Name "Ethernet"
"Ethernet enabled, Wifi disabled"
}
I use to do the same thing when I lived in the boonies and had a metered connection.