My switch is similar. I only used center pin and one other pin. I snipped off the 3rd pin.
I did get it working. Oddly, some of the gpio pins only want to work as in or out.
I’m using gpio5 and gpio46 on the switches.
root@LEDE:~# cat getsw
#!/bin/sh
echo gpio5
cat /sys/class/gpio/gpio5/value
echo gpio46
cat /sys/class/gpio/gpio46/value
Flipping switches and running above commands a few times, I get…
root@LEDE:~# ./getsw
gpio5
0
gpio46
0
root@LEDE:~# ./getsw
gpio5
1
gpio46
1
root@LEDE:~# ./getsw
gpio5
0
gpio46
1
root@LEDE:~# ./getsw
gpio5
1
gpio46
0