I selected Two-Factor Authentication via my iPhone 12 and want to turn it off

I have read through a number of threads on how I can turn this off, but I keep going in circles. The reason I want to turn it off is because my iPhone is linked to my sons iPad that he uses at school. I don't want the 2FA on his iPad, as he won't know what to do. I turned on 2FA today (21st May 2021), so I am well within the 2-week window to be able to turn it off. I have tried to turn it off via a PC through AppleID account, but I don't have the option to turn off - even after clicking on 'edit' within Password & Security. There is simply a greyed out 'on' under Two-Factor Authentication. So I thought the only way I will be able to turn it off is through the enrollment confirmation email. I have checked my email inbox, junk and spam folders and I have not received any email/s whatsoever from Apple regarding 2FA enrollment. So, I am caught in a dead cycle of nothing. Please help if you can! I am kind of clinging to the hope that there may be a delay send on the enrollment email from Apple. You see, I only turned on 2FA 4-hours ago at the time of typing this.