It's tough. iperf is a reasonable tool. It works by setting up tcp connections and actually transferring data. I like the work https://fasterdata.es.net/ https

It's tough. iperf is a reasonable tool. It works by setting up tcp connections and actually transferring data. I like the work https://fasterdata.es.net/ https://fasterdata.es.net/ does. They provide clear guides and set expectations if you want to get more bandwidth out of a connection.