I'm not allowed to "replace" worlds on realms

Put the summary of the bug you're having here

What I expected to happen was...
I thought I would be able to set up a realm using a pre-existing world that we started working on together 

But...
A realm with a random seed was created and it won't give me the option to replace the world on the realm with the pre-existing one, or even allow me to choose the seed of the pre-existing realm so that we could just start over.

Steps to Reproduce:
1. Go to a mc world
2. Press "Play on Realms"
3. Buy a new world, then go to the settings

4. Press "Replace" and it won't let you, even if you restart the game or buy a new subscription 

 

 

 

 

I’m on v1.16.50 bedrock but all the links sent me here