Google Fit doesn't record steps accurately

I have been very frustrated trying to get an accurate record of steps in the Google Fit app. I have only one device, a Fitbit Sense watch, which counts my steps, and I have disactivated activity tracking in the Google Fit app. I have specified that Fit can receive steps data from another app. However, Google Fit always has a considerably lower number of steps. The difference is not consistent; it can be 70% to 80% of what the watch records. It is always lower. The watch transmits the steps accurately to another app, so the fault cannot lie with the Fitbit Sense app. I noticed that in the Fit app, the steps are broken down by minutes the walking started. Is Fit consistently rounding down? I want the steps transmitted to Google Fit to be recorded as received, not reworked in any way. I have three apps which show steps; two are in agreement and one is way off. This is not satisfactory.