Saris M2

I have my Saris M2 on 2.5 turns I have calibrated the Saris on Saris Utility, but couldn’t find the spanner icon on Zwift to recalibrate there but apparently the Saris calibration was successful but still have issues on ERG mode.
From the calibration my new roll down time is 3.976 but I have literally no idea what that is.
The ERG mode is the issue whereby feels like I am riding through mud.
I would appreciate any support to help resolve this issue.