Only Memory Game is showing in the frontend. Creating and editing the content does not have any issue.
Issue reported: https://h5p.org/node/1075748
Test pages:
https://numeko.info/adventskalender/
https://numeko.info/adventcalendar/
Note: There are no errors in the browser console
Another user is reporting this issue and was able to resolve it by downgrading WP to V5.5. https://h5p.org/node/1091992