USB tethered Celluar WAN Failover Auto-Config

[fubar24]

I have a dedicated OpnSense setup running on a older PC. The primary WAN is a Cable Internet service.
I have a working "Failover" WAN using my Android Phone connected using USB tether.
When I drop my phone in the USB cradle, OpnSense detects it, but I always have to manually go to "Interfaces", select the "WAN Failover" device, then click "Save", "Apply Changes" for it to become live as my secondary "Failover" connection.

My question is, how do I make it automatically configured when I connect my Phone (without having to "Save" "Apply Changes" every time)?
Do I always have to manually configure it each time?

[fubar24]

Is there nobody that can answer this question? Please..