Connect ISP Optical Cable into Turris Omnia?

But that only speaks ethernet, if you only need 1 Gbps, why not simply use the already existing sibling rj45 socket port?

My first hand experience is still zero, I have neither optical links at home nor anything else in my omnia’s SFP cage/port, I was just relaying information I learned in the forum. Here is a thread that might be helpful:

there was/is a community wiki, but I can not reach it at the moment, so it might be gone for good:
https://wiki.turris.cz/doc/en/public/sfp