Display content from a remote URL
Creating a custom module for this in Drupal would be quite easy if you focused on your specific use case.  You can find more info on that here:
https://www.drupal.org/docs/8/creating-custom-modules

More specifically, you may want to look at a custom block implementation:

https://www.drupal.org/docs/8/creating-custom-modules/creating-custom-blocks