My LTE modem picks up LTE B4 at 30% and B12 at 55%. B4 is much high data speeds but it keeps switching to B12. Is there a way to lock it to B4?
Yes there is a way but it is not something you could do easily from the GUI and would be specific to the core module used in the router.
You would be sending the specific AT command for that module in a while loop on boot to set that up.
As it would be specific to the module you would need to go Digi Technical Support or your Digi distributor for the exact command.