My iPad is giving me a rk code and it says that I have lots my trusted device

Rk code iPad is Recovery Key code

See this topic: If you’ve ‘lost’ your recovery key ‘RK-‘ : https://discussions.apple.com/thread/8469226

enter your current valid AppleID password and immediately after 6 digit code eg Hello123456 without any spaces. Tap done. Three ticks should appear next to fields and you’ll be logged on, without the RK- prompt!