Hello Matas,
just for the information that most of this data usage came from AWS, In/Outgoing traffic on LAN is blocked, theres only one static lease allowed to talk outside, this device is actually disabled and the traffic from AWS didnt stop.
The VPN is not in use and the history shows <1 MB the last 10 days.
With 20 January the extreme data usage started.
I will try to update the device and hope the data usage will stop.
Thanks