Cannot upload saved world to realm

I had a multi-person Minecraft Realm on Nintendo Switch that I was notified a couple of weeks ago would expire and not be renewable, but that I could backup my world and upload to a new Realm. 

Once my realm expired I tried doing just this, but I immediately get error messages every single time I try uploading my backed up world to a new realm. I've opened 3 new realms since and spent countless hours trying to fix this and still no resolution.

I contacted support and was told to "just keep trying." Hours later, I'm still here unable to access a game and shared realms I've paid for.