Greetings, Charly’s post gave me an idea. I just now deleted the knowndevices.xml and prefs.xml files, located in the Documents-Zwift folder.
I started Zwift, paired my current devices (Saris H3, HR Strap, Cadence Sensor), chose ride, and then menu and settings and updated my choices for settings.
I then rode for 10 minutes on the New York world and my Saris H3’s resistance and corresponding power (Watts) responded as expected. I’m very pleased with this result. I do not know if this will address the issues that others in this thread have experienced, but this definitely worked for me.