Apple watch high data usage

Hi,

I recently got an Apple watch 7, this morning I get notification from my mobile operator that I

used up my whole data (50GB). After checking the report I realized that since I

wear the watch it had an extremely high usage: Day 1 : (13.92 GB)  day 2: (9.82 GB) day 3 (12.81 GB)

and today from 12AM-8:23 AM 4,97GB

Two higher numbers could I relate to when I had a very short walk outside ( 2 km)

The watches Cellular (E-SIM) is not activated, SIRI on my iphone is not active. There was no

significant changes in the Battery usage on the watch or phone.

When I check my iPhone data usage, the data used in the whole period ( 462 days) is about 318 GB, which in average should be less than 1 GB/day.

I would like to understand what app/ apps could manage to use this much data, and how can I

stop the watch/ iPhone to drain so much.

Thanks in advance for your support