Since upg of version 26 on my iPad pro, the colums of the mail app are persistant

Since the upgrade of my iPad on ios 26, the colums in the Apple mail changed and are persistant. The iPhone is not changed and this is good. How can I remove the persistance of the folders, which I don’t need when I am inside the folder and return to the old look where you had arrows to get to the next Message and the folder Icon? It stresses me a lot, because I have less space to read my mails.