Hello,
How frequent are the disconnects?
The troubleshoot file you have attached indicates, that at the moment, when troubleshoot was downloaded, the device was registered, connected and able to establish data connection through it.
In the logs from May 13 to May 16 no disconnects are recorded. Did anything happen within this time frame? At the moment it is difficult to estimate the cause of the issue. If possible, download troubleshoot, when disconnect occurs.
I also see, that you have Ping reboot configured to restart the router. Instead, I suggest to select Modem restart option instead of the complete device reboot to try to reestablish connectivity.
Another note is that the firmware your device is using is dated. It is advisable to update to at least the the latest legacy firmware from here.
Best regards,
Žygimantas