If you have noticed an increasing number of issues being closed with this text or something similar, you are not alone. Support for Drupal 9 is ending. Issues that cannot be reproduced in a supported version of Drupal are being closed.
If you are still running any version of Drupal 9, you need to make your project/product/service owner aware that while contributed modules may still indicate that they will work with 9 (or even 8), there are increasingly fewer installs of this soon to be unsupported versions of Drupal core, Symfony, PHP and CKEditor and MUCH less manual and automated testing being done on unsupported versions. If you’ve decided to continue running unsupported code, you may want to pin the contrib versions of modules to the version they are on now in your composer.json. If you continue to apply module updates that are only being tested with supported versions of Drupal core, other contrib modules, Symfony, PHP and CKEditor, the likelihood of changes introducing bugs increases with time.
The Drop is always moving. To benefit from all the bug fixes and improvements from thousands of developers around the world to Drupal core, Symfony, PHP and CKEditor, you are going to need to move with it.