I've seen it on YouTube...finally had a chance to try it.

The staircase...

https://i.imgur.com/baW8aRn.jpg

The Queen size box spring...

https://i.imgur.com/LA9zYeQ.jpg

The happy Queen...

https://i.imgur.com/5m3zmXb.jpg

It was actually *way* more work to wrestle the actual
mattress up the stairs than it was to cut the box spring,
carry it up and then repair the frame.