I would return 404 in case of resource does not exist(means the url path is wrong) and i will return 400 only if the rest call is made with some invalid data (@PathParam) for example
https://api.domain.com/v1/profile/test@email : here i am trying to get profile of email id, but the email itself is wrong, so I will return 400.
https://api.domain.com/v1/profile1111/test@email.com will return 404 because the url path is invalid.