I have Collabora install on the same server as a nextcloud instance. Both are installed natively (not docker), nextcloud from source, Collabora from the official debian packages.
Collabora worked quite well at version 6.4, but since upgrading Collabora is super slow to initialize when you click on a file in the nextcloud file browser. It gets stuck on this page:
I timed this at just over one minute, which almost makes me think it’s waiting for something else to time out for one minute.
Ubuntu 20.04.3 LTS