The workouts are based as I understand on heart rates, but I am in beta blockers which reduces heart rate and the lit suggests one ignore zones on beta blockers ….
so is there any mechanism in game to address this, and if not, others who have suggestions?
You can lower your maximum heat rate in game to adjust your zonal range.
That said I’d strongly advise seekingmedical advice specific to you rather than taking advise from others in a similar position to you that s actually might not be the best for you.
I am not looking for medical advice. Been on same meds for some years 
Problem is with how game frames zones giving those with pharmaceutically reduced heart rates inaccurate fitness reporting.
I will look into the suggestion you iffered.
Thanks
Use Brawner formula to set HR_max to 164-(.7*age)
And see Page 20 of Aerobics 2019