Xbox error and realms

Hello we have pe on my tablet and phone which we could use as 2 player at home. My child child updated both and said it was not possible to play 2 player mode it worked for a couple of seconds and then stopped.

They surfed and was told to set up an xbox membership and it downloaded realms.

I don't wish to pay for something which I could get for free especalls as it is my child playing both games simultaneously (don't ask)

My questions are this
1. Can I reset the game back to pre update so that we can no longer have it linked to xbox (we don't have an xbox)

2. If I reset will they lose their world's they have spent months building.

3. Can I keep the game but put it back to windows

4.Can I back up the world so we don't lose them.

5. Can I uninstall realms?

Thank you so much