Our house was pretty much your Iron Fortress, minimal contact with the outside world, no shopping, no visits, groceries curbside delivery, then quarantined in the garage before being brought into the house, etc., etc., etc.
We all got it anyway.
Only confirmed when my nonagenarian mom needed to go to the ER for rehydration, they wouldn’t let her go without a COVID swab.
We’re out of quarantine now. I’m looking and becoming a convalescent plasma donor, if they don’t disqualify me for being too old or some other reason.
We can reduce our risks, but never fully eliminate them. I hope you and your family are all doing well now.