"tell us your current linked email" in response to me saying i dont KNOW the current linked email

im really just asking this to know if theres any point in contacting nintendo further about this or if my accounts just fucked honestly - i made my switch account when i was like 12, so now its been like 7 years and i have no idea how to actually log into the thing. i dont know what the password is and the nintendo account user in the user settings isnt an email address, its just the first 3 letters of an id. i have a feeling i know what that id is but the password i have written down for it didnt work when i tried to log in online. my actual email im fairly certain is linked to an alt account. i dont know if its linked to a parent account, and even if it is my mums going to have no idea what the password for it is. i tried to contact nintendo about it and it says in the email "If you can't recall your current linked email address we will not be able to assist you further due to privacy reasons." is there any chance im getting into my account or no lol. and is there any way i can still transfer my game data to a new switch without logging in (ive only just got switch online for the first time now so ive never transferred anything before). thanks for any help anyone can give