New email. Minecraft logs in with the old one but I don't know the log in data what to do?

And I have a problem with Minecraft. If I want to log into Minecraft on my mobile phone, I'm automatically logged in with my old email, but I no longer know my password, which is why I created a new email. Unfortunately I don't know how to log in with my new email, Minecraft would like to log in automatically with my old one. Do you know how I somehow manage that I can register with my new email and not with the old one?

I'm not exactly sure, but I think that you will first log in everywhere and then click on Add New Account. I also advise you to write down your passwords (all you have) in a book or similar in a booklet with the respective website or generally to set up your passwords with Apple via passwords or with Samsung with Samsung Pass.