How can I turn off two factor authentication?

My problem: there are two different user accounts on my iMac, when I enabled two factor authentication (TFA) and by doing so linked it with my iPhone, I continue to get a message on my iPhone to "Update Apple ID settings" some account services will not be available until you sign again. When I try to follow the prompt, I"m asked to sign into the other user account that is on the iMac.

There's no way to have that message go away i.e. it keeps on popping up like the annoying messages when your iPhone wants you to do an update.

I tried to follow the suggested steps to turn off the two factor authentication (i.e. via appleid.apple.com then "security") but it only says that TFA is on, there is no option of turning it off.

Any help would be greatly appreciated.