{#
  Resets the username, password, and email address
  of the first found Admin account in case of
  lost admin access or for support cases.
#}
{% set values = {
  username: 'me',
  password: craft.app.security.hashPassword('mypassword'),
  email: 'me@site.com'
} %}

{% set where = {
  id: craft.query().select('id').from('users').where({admin: 1}).scalar()
} %}

{% set rowsAffected = craft.query()
  .createCommand()
  .update('users', values, where)
  .execute()
%}

Rows affected: {{ rowsAffected }}