I see... you should consider using it. Otherwise, you will have to:

async function handleSubmit(values) {
    try {
      let response = await signUp({
        variables: {
          email: values.email,
          password: values.password,
          familyName: values.lastName,
          givenName: values.firstName,
        },
        refetchQueries: [{ query: UserDocument }],
      })
      if (response.status === "FIELD_ERROR") {
        // handle error here..
      }
      router.back()
    } catch (err) {
      console.log('err', err)
    }
  }