Really needing some help here, I’ve followed all of those instructions including the one where you install the old version of richdocuments to no avail. I seem to be getting a different error.
I am running Debian 10.11 with Nextcloud 23 and Collabora 5.0.1 now. PHP 7.4.26. Single server with the Collabora Online - Built-in CODE Server installed as well (21.11.6). Old version 4.1.2 of Collabora also did not work so I just updated it. No docx or xlsx document will open, they just try and download to the desktop. The only error I see in the nextcloud log is this one:
GuzzleHttp\Exception\ConnectException: cURL error 28: Operation timed out after 10001 milliseconds with 0 bytes received (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) for https://nextcloud.domain.ca/apps/richdocumentscode/proxy.php?req=/lool/convert-to/png