I don't think you understand what seeing a 4k image or video means. You can't see a 4k image or video without a 4k screen. Maybe a 15 year old camera can capture it, but you can't see it, even with today's phone screens.

The only TV I've ever owned was like 19". The only real-size TVs I've ever watched are my parents' and the one my roommate had in the living room.

And just because they've been available since 2019 (according to you- I honestly can't remember when they started showing up lol) doesn't mean they were common or cheap at the time. And both of those units (the ones I've spent any time with) were bought around 2016 anyway. Not sure what world you live in where everybody buys a new TV every 3 or 4 years, but it's not a universal thing, or even the norm. Where having an SDTV might justify a midnight trip to go get a real TV, the need for 4k is less than 0.

So no, I am quite sure I've never seen a 4k image or video. Because I've never owned it has access to a 4k screen. That in and of itself is enough to verify that much, without having to worry about how modern it is, it what it was shot with, or recorded on, or how it was downloaded, or where/how it was streamed or any of that confusion.

No 4k screen means I've never seen anything that could only be on one.