iperf3 is installable via scoop and yay. You simply run the server on one computer and point the client at that IP from another computer.

 powershell

    
# On one computer
iperf3 --server
# On another computer
iperf3 --client <ip>

  

You can get your IP address on Linux like this. For Ethernet look under (probably) end0 and for wifi (probably) wlan0.

 powershell

    
ip addr

  

On Windows you can use Get-NetIPAddress.

 powershell

    
# For Ethernet
Get-NetIPAddress -InterfaceAlias Ethernet*
# For Wi-Fi
Get-NetIPAddress -InterfaceAlias Wi-Fi

  

If you're diligent about firewalling then you'll probably need to open up the port (default is 5201)