Which of my phones, computers and gadgets no longer get security updates?

“Which of my phones, computers and gadgets no longer get security updates?”

An inventory of every household phone, computer, tablet, router and smart TV with its model, operating system version and owner, each matched to its maker's security-support end date (from endoflife.date and the maker's page it cites), devices already unsupported flagged, reminders before each end date, and the options for each unsupported device laid out: update, extended security updates, a supported free operating system, keep offline, recycle or replace.