Update: I managed to get it working - a simple typo prevented proper working.
YET NEXT PROBLEM: When I want to edit a document it only works when I first add an exception to the browser for my documentserver, due to self signed certs. I can connect and change settings with any browser and from everywhere. Error message was:
ONLYOFFICE not reachable. Contact admin
Hence, no one but myself can edit documents as one needs to be within my LAN to be able to access documentserver-IP and add that exception.
Any idea how to somehow mask the different containers for borwsers so that the browser assumes everything is coming form nextcloud?
Btw. I also tried to use the nextcloud internal document_community (server) app - with exactly the same error message. Of course after pointing the onlyoffice app to the internal server appโฆ