In case anyone is reading this, you can confirm the metric of each connection through the LUCI page (i.e. the “Advanced” settings) rather than via SSH if desired.

Select the “Status” main page and the “Routes” sub-page under status.
That page will show active IPv4 (and IPv6 now) routes, as well as the metric for each route.
The lower the metric, the higher the priority (think place in a race so 10th place comes in before 30th place.)
I.E. I have a WAN connection to my ISP and my phone tethered via USB (and of course LAN connection.)
The LAN connections are all the first priority, so have the lowest metric (“0”).
The WAN (ISP/wired) connection is the next priority in routing, so have the second lowest metric (“10”)
The USB tethered phone is the next priority for me, so has the largest metric (“30”)

Note there is no “20” metric for me, as I don’t have a WiFi repeater failover set up. If I did, it would be the “20” metric, and therefore would be used after the WAN/ISP internet connection failed but before the USB tether was used (“30”).