Xbox One Minecraft World Vanished

Good morning,

I'm here to report yet another Minecraft world vanishing for no reason on Xbox One. This is
not the "Xbox One Edition" but the full 'Minecraft'

Please also note that this particular world has been in regular use since the very inception of Minecraft for Xbox 360 (May 17th, 2009). In this time, through all the updates, conversions, etc, we have not once had an issue like this before.

A timeline of events is below:

• Monday, July 22nd 7:00pm EST, the world is loaded from a saved file and 5 friends continue their adventure.
• Monday, July 22nd 11pm EST, the friends depart and the world is saved and closed appropriately, followed by the powering off of the Xbox.
• Tuesday, July 23rd 7:00pm EST, Minecraft is loaded as usual but, to my dismay, it has vanished. The only remnants are of a back-up copy of the world which had been made roughly 20 days prior.
  • Frantic, for fear the the past month's tremendous amount of work has been for naught, I search thoroughly through the saved game data for any clues as to what has happened.
  • Sadly, nothing can be found.
  • In a desperate effort, I frantically search the internet to see if I'm not alone; I'm not.
  • After trying many suggestions by the internet warriors who have faced this vanishing evil in the past, including all of those suggested
    
    here I have not recovered my lost world.
  • I have also logged into Minecraft on Windows 10 but have not found my missing world there either.
  • My final effort today will be to attempt the mysteriously-claimed solution of removing my account from my xbox and re-adding it.

TL;DR - World vanished, I've tried every suggestion I can find except removing my account from the Xbox, thus forcing a re-sync, but if anyone has any other suggestions I can do before that,
I'd be happy to hear them because this world is very precious to me and my friends since we've been playing on it for over a decade straight.

I DO have a backup of the world, but it's not a very recent one (my fault) so it would be amazing if we could get it back without having to lose all our work.

:)