So I just signed up for a 30 day free trial on this and it doesn't work? So after the fix do I get to actually have my free trial or straight up pay for it? Disappointed right now.
They should make that thing where older iOS try to download an app and it downloads the last working version (i.e. 1.12.1) until they resolve the issue because there's no way to do that manually. I think there are many of us who lost our worlds trying to reinstall 1.13 and just want to be able to play again.
So after some extensive tinkering I managed to upload my world to realms from my ps5.
I had to login to my router settings and change Nat type to open. I also had to add my ip address from from Ps5 to the settings in the router which according to the warning messages leaves my ps5 open to hackers.
Long story short, it worked and now I can play realms. Check your router settings and just do some tinkering it'll eventually work.