A little embarrassing - I've lost/forgotten the login page for a Drupal 8.9 website. It was renamed using the module "Rename Admin Paths."
I've gone to the module page at drupal.org and looked through issues and comments, but none of the solutions I found will work.
This site is unable to install Composer or Drush at this time, so I can't use any method there. Another suggestion was to search the 'variables' table - but that was specific to D7, I believe. I don't see that table.
I've commented within their page hoping to find the answer, but maybe someone here happens to know the answer?