I use the Docker Collabora not the Appimage but updating my Nginx (https://sdk.collaboraonline.com/docs/installation/Proxy_settings.html#reverse-proxy-with-nginx-webserver) solved it for me. They changed “lool” to “cool” which broke literally everything in the reverse proxy plus changed the “static files” location.
Copying and pasting the changed locations from the link above fixed it for me using 5.0.1 of the app.