Is your Drupal Core refusing to update from 9.4.3 to 9.4.5 (or higher)?
I had the same issue and found https://drupal.stackexchange.com/questions/312436/why-is-composer-refus… so I could be sure I wasn't the only one with that problem.
Finally I found the reason: It's modules which still (wrongly) implement the
key in their module .info file!
So if you're running into such an issue, try the composer command:
composer prohibits drupal/core 9.4.5
to find out which module is broken.
Then look at the module issues, if there's already a fix available. If not, create an issue.
The fix is to remove
from the module .info file and instead use:
core_version_requirement: ^8.8 || ^9
See https://www.drupal.org/node/3070687 for details!
So it seems something has changed in the version comparison at (Drupal) Composer or Core.
Update: The root cause seems to be this change: