Question about wallet security

Is it possible to have a seed phrase but separating it from a wallet? As in: What a password is to a username to authenticate any user account?

I'm irritated that the seed phrase *is* the key to the wallet without there being a door for that key.

I would like if I could store the *username* part and the *password* part separately, so that in case someone accidentally finds my seed phrase they still wouldn’t know what to do with it because they can’t find the door.

Sorry if this is a n00b question.

Edit: the username/password analogy was examplatory. I'm aware Bitcoin doesn't have user accounts. I was looking for a security layer that is stored separately from the seed phrase, and a passphrase seems to be the way to go here. Thanks everyone

Edit 2: u/BuyRackTurk’s comments made me lean towards not using a 25th word and instead focus on keeping the main seed phrase secure, which is a whole other area.