Saris seems to be active on their Youtube channel on the H3 quickstart video, they’ve been consistently replying to comments. They did reply to my comment when I wrote that I wouldn’t recommend the H3 for use with Zwift.
I hate to say this, though since they haven’t been replying through their support one has to find a better way to get their attention on the issue: at this time, you are better off commenting on their H3 Quickstart video on YouTube. They seem to see incoming messages, and they seem to at least provide answers that are not an automatic reply like the one you get through their support email.
I’d encourage you to post on their YouTube channel if you’d want to bring more awareness to the issue.