How do you use my icloud to log in to a new device if I no long have the previous device or the its passcode?

I cannot log into an Ipad 2 with my Icloud account because it is requesting a passcode on an Iphone 5S that I no longer have and cannot remember.

When I click forgot password, it asks me to to approve the device from another device logged into the account.

However, it seems like the device is already approved on my icloud. A few minutes later, it logs itself out after a waiting screen as it is unable to proceed. I feel like I'm going in a circle.

Anyway to remove the the passcode on an account for a device I don't have? Something about end to end encryption but its too complicated for me.