Create item with relation

Help
1

I created a table that will be used for a form to great an organisation as part of an onboarding flow
I want to use the graphQL mutate function however when using it it requires that i create everything the form and the related tables even though the data already exists. Why is it this way?
eg. adding applicant_id that has a relation with user. However i just want to add the userId which is the foreign key relation to users table.

mutation {
  create_tbl_payeeapplications_item(
    data: {payeeapplication_data: "{}", applicant_id: {user_id: 273314}} 
  ) {
    payeeapplication_uid
    applicant_id {
      user_uid
    }
    status: payeeapplication_status {
      payeeapplicationstatus_id
      payeeapplicationstatus_name
    }
    payeeapplication_data
    payeeapplication_active
  }
}