I have 2 type of 4G modems working with RV 320 but as the router using ppp protocol it limits the throughput around 21 Mbps. 

I have tried Huawei E398 and ZTE MF820D LTE modems, both of them are working but with slow 14/3 Mbps throughput as they would be on 3G network only. I have bought this router because I would like to swap out the TP-Link TL-MR3020 4G router from the W...