Updating dependencies according to these instructions offers an older version of the module. Composer.json file has the package required as
"drupal/h5p": "^1.0@RC", and it used to update just fine. It seems to be stuck with version rc14 and unable to recognise any changes. It seems like a problem with packages.drupal.org being unable to update the package info.
The instructions on creating an issue about it here seem to be outdated as that is for a Drupal version 7 project.
Any ideas how could that be resolved? A newer version has been released in the meantime and the package manager is still showing the rc14 one.