Hello,
Kindly find my answers to your requirments:
When no wifi network available or wifi network down, then uses of my data SIM card:
- You can enable the failover function to allow you to switch to your backup interface incase of your primary one goes down: Find link for Failover
This rebooting takes couple minutes, that means fail on game or losing time of movie:
- Can you disable the Auto Reboot function to avoid any rebooting circumstances, Find link for Auto Reboot
Best Regards