RBR50 and RBS50 combining with a 4G modem?

[rjvanvugt]

Hi! I'm currently running a RBR50 with one RBS50 on a fiber connection. Works like a dream. I will move to another place, and will have to rely on 4G for the first few months, and after that I will switch back to fiber again. I'm looking for the cheapest and most simple solution that allows me to roughly keep the same speed and to keep using my RBR/S system / will not push me to spend a few hundred bucks buying another modem/system that becomes useless once I switch back to fiber again.

I can change the RBR50 to a LBR20 and use the RBS50. I will have to buy a LBR20 for this, and the system will be slower due to the downgrade from AC3000 to AC2200, correct? I will also not be able to use the RBR50 in this setup, as it will not function as a satellite? 

Is there another way to keep using both my RBR50 and RBS50 and connect my RBR50/RBS50 with just a 4G modem? I've seen some modems/routers with ethernet connection, how would that work? How compatible are other brands with Netgear in this case?

Any other solutions that I'm missing? Other Netgear 4G modems that should be able to work with the RBR/S50 set?