Monitoring Network Traffic Utilization in mwan3 Usage

Hello. I always receive a lot of information and help here.
I am developing a router for use on ships. However, it's not easy as I'm not an expert in this field. I eagerly await your response. Please help me.

My router has multiple WAN interfaces and one LAN interface. It is configured to use only one WAN network interface based on dual priority.

In the maritime environment, network costs are high. Therefore, even if multiple WAN network interfaces are active, a specific network interface that should be used with priority has been determined.

For example, if there are wan1, wan2, and wan3:

wan1 has priority 1,
wan2 has priority 2,
wan3 has priority 3.
So, when all WANs are online:

Use only wan1 to handle network traffic, and do not use wan2 and wan3.
If only wan2 and wan3 are connected, use only wan2.
wan3 has the lowest priority.
To implement this, I configured the metrics and weights in mwan3 as follows:

I assigned these to all rules as policy members in the order of wan1, wan2, wan3.

[test]
In the case where wan1 is not physically connected to the network, but wan2 and wan3 are connected:

(I need only wan2 to use 100% of the network traffic.)

[result]

luci> status > multiwan manager > status

[[Questions]]

Q1: Where and how can I obtain information indicating that only wan2 traffic is being utilized? In this case, the result obtained from the mwan3 status command is like this: "wan2(100%)". Is there a way to confirm wan2(100%)?

Q2: I have confirmed that ping is being sent to trace wan3 for failover internally. However, in a maritime environment, sending ping continuously also incurs costs. I'm curious if there's a more efficient way to manage this for failover.

The purpose of my project is to automate network switching according to policies at the minimum cost. I greatly appreciate any valuable opinions from those with better ideas. Thank you very much for your assistance. Thank you.