LB2120 4G modem as backup in case of normal wired service outage

[StarWars1977]

Hi,
I'm new here and have a plan to buy an LB2110 for backup. I need it in case the cable provider has an outage. My normal router is a Synology RT2600ac, which supports the backup mode on it's 2nd WAN port. In failover mode it automatically changes between WAN ports.
I have been told, that LB2120 has some generic issue and because of that it doesn't allow my Synology to change on LTE provided network as it (LB2120) need to be rebooted every time when need to be use, if the Netgear is in bridge mode.

I hope it was not too complicated, as I desribed.

Is anybody using this router in a similar way? Does anybody have practice with it?
Can anybody inform me how this 4G router works? (What I expect is that LB2120-100PES - European version - working, collecting and transfer data to the other router's WAN2 port and the other will it use if needed - automatically, without I need to reboot it, or simple turning on.)

[FURRYe38 · Accepted solution]

Netgear has set up a community forum specifically for the Mobile Router products. Most of the people who watch that forum are more likely to have experience with mobile routers and know how to work it better than those of us who follow this router forum. Might be more likely to find someone who has a solution if the question is posted there:
https://community.netgear.com/t5/Mobile-Routers-Hotspots-Modems/bd-p/aircard

Please use this link to the main forum product list to review and choose where to make your posts. 
https://community.netgear.com/t5/NETGEAR-Forum/ct-p/en-netgear

Thank you

[FURRYe38 · Accepted solution]

Netgear has set up a community forum specifically for the Mobile Router products. Most of the people who watch that forum are more likely to have experience with mobile routers and know how to work it better than those of us who follow this router forum. Might be more likely to find someone who has a solution if the question is posted there:
https://community.netgear.com/t5/Mobile-Routers-Hotspots-Modems/bd-p/aircard

Please use this link to the main forum product list to review and choose where to make your posts. 
https://community.netgear.com/t5/NETGEAR-Forum/ct-p/en-netgear

Thank you