I’ll say it again, why not just build in the Peplink Broadband-Speed-Test utility which can utilize Apple, Google, and Microsoft servers or custom URL’s? That way you don’t need a dedicated Peplink device on the server end. This is a great utility that can’t easily be fudged to make sites like Ookla look falsely fast!
https://download.peplink.com/files/Broadband%20Speed%20Test%20v3.1.exe
Scroll down on this link to see it referenced: Combining the bandwidth of all WAN links. 3M + 3M = 6M?