Without knowing what data the device use it is difficult to suggest how you can minimize the data consumption.
This forum post contains some tips on how to reduce the data consumption:
We use these BR1 mini devices at multiple sites for this client, so not one sites are really the same… some require direct RDP connection only. Some require internet for mails, some for VoIP and other systems etc.
What I did notice is that they consume a lot more data (GB) over the PepVPN than straight internet connection.
The devices are set up to run on a LTE 4G connection using PepVPN to reach HQ…