Teltonika RUTX50 5G/4G-modem & dual band WiFi & 4-port router, dual sim, load balancing, 4 x SMA female for 5G/4G antennas & 2 x RP-SMA female for WiFi antennas, 1 x SMA for GPS antenna, unlocked

Capable of 5G speed up to of 3.3 Gbps.
4G CAT20 compatible.
Two SIM card slots, you can use failover or load balancing.
5 x Ethernet ports, 1000 Mbps. 4 x LAN & 1 x WAN.
Wi-Fi 5: 2.4 GHz and 5 GHz.

With a 4x4 MIMO antenna (not included) you can get almost anywhere significantly increased internet speed if the operators base station is further away. 

Failover
The failover function enables use of the internet connection that is operational. The WAN port of the router can be connected to another modem or other internet connection. The router itself can also be connected to the internet in several ways (2 SIM cards, i.e. 2x 4G or 5G connections or xDSL modem.)

Load Balancing

Load Balancing is a method of distributing the traffic between different internet connections. Load Balancing can be used to distribute the data load between different interfaces and increase overall Internet speed for multiple users and
for connections. It is important to note that Load Balancing does not increase speed for any single connection. For example, if you load a large file, using the Load Balancing function does not increase the download speed.
However, with Load Balancing, the speed of several connections can be increased.
For example, when used on a WiFi network, Load Balancing would use the resources of several WAN connections for different process requests made by different customers.