Omnia: Use GPIO input to switch to LTE modem

Hello,

Would it be possible to use a Turris Omnia GPIO input pin to toggle between the existing ISP connection and an attached LTE SIM card? I would like to make the LTE SIM card connection the primary internet source when I flip a switch and vice versa.

If so, has anyone successfully done this? Is there material available to step me through this setup?

have you looked at https://openwrt.org/docs/guide-user/network/wan/multiwan/mwan3 ?