How to remove realms you don't want to see?

You will see a folder with all your config data next to the app called AzerothAuctionAssassinData

Go into the folder and find the file for your game mode, for example EU Season of Discovery is eusodclassic-wow-connected-realm-ids.json

Open the file in a notepad, sublime text or another text editor:

Remove the realms that you don't want to see and ask chatgpt to make sure you have valid JSON. Here we can reduce the scan to just the Wild Growth realm: