iCloud Mail on iPhone continues to occupy storage despite account deletion

Mail in Phone Storage on iPhone shows taking up the most storage space of <3GB. Offload App, and delete app will not delete it. All accounts were claened with files deleted from the Trash folders, and all accounts were removed. Hoever, the stoarage size of Mail is not changed. I do not need Mail as I use Yahoomail for all emails, and still have gmail and outlook too. Any help would be greatly appreciated.

[Re-Titled by Moderator]

Original Title: iCloud Mail on iPhone still shows taking up &gt;3GB iPhone storage even though all the accounts were deleted.