alzhao
2
You can try using another USB modem. It will use its own antenna. Generally the antenna will be OK because it is optimized for your area if you bought from your carrier.
You can set up but only with tech skills. You will see multiple modem devices and have to set up manually, by modifying /etc/config/network
Failover and load balancing is possible as long as you set the correct options in /etc/config/network and /etc/config/mwan3
I have to say that this is not recommended because it may be difficult to set up.