There is no option in #Instagram now to stop it suggesting your profile in the app to other users who know your e-mail address or phone number.
There used to be an option to disable suggestion. #Meta removed it and replaced the section of the options where it used to be with a link to Meta Accounts Center (which no longer includes the option). You can disable suggestion on the web interface but that makes no difference to what happens in the app for you or others.
How is this legal?