I have altice fiber, gig speed. I recently got a technician to come by to try and fix this problem and they gave me the latest gen modem, router (cable box) and wifi extender (wifi extender is irrelevant to the connection issue. but thought I would mention)

Every now and then, starting with the old gear to now, I would just loose internet connection (connected without internet) on both ethernet and wifi devices for an untold amount of time. I do power resets factory resets, check optimum outages, faqs, calling support and nothing. No concrete answer on why or a solution untill it randomly starts working again.

I don't know if this is common and everyone I know doesn't experience this. For everyone online its device specific. Could it be a dirty fiber cable? Bad modem (the wired cables are in the modem) or just shitty luck?