Here is the browser log entry after I select, right click and select copy
The collabora_error.log is empty.
The nextcloud_error.log has
[Fri Apr 11 10:29:13.098923 2025] [proxy:warn] [pid 201939] [client 93.174.93.12:60000] AH01092: no HTTP 0.9 request (with no host line) on incoming request and preserve host set forcing hostname to be nextcloud.phagex.eu for uri /
Here is the link to the last line of the nextcloud.log Nextcloud.log - Google Docs
I hope this makes sense for you now.
If you have a more recent tutorial, I am more than happy to read it if you point me to it.
Here are the changes I made to KarlF12’s protocol (quoted from the original post).