Help needed: Unable to reach collabora

I recently set up a VM for NextCloud and Collabora.
Everything went fine until the Collabora installation.
My machine is not reachable from outside my local network, so the domain structure is different, and I can’t use Lets Encrypt.
I followed this guide here:
Now, when it comes to running the docker container, instead of the example, all I have is “nextcloudtest”, the fqdn of my machine. https nextcloudtest/ takes me to my nextcloud webUI.

Q1: Is this the correct format?
docker run -t -d -p -e ‘domain=nextcloudtest’ --restart always --cap-add MKNOD collabora/code

Now, in the browser, http nextcloudtest/ takes me to https nextcloudtest/ which displays the NextCloud WebUI correctly, http office.nextcloudtest/ correctly points to https office.nextcloudtest/ but only shows the default apache success page. There are no other web services installed, there are no other files in sites-available or sites-enabled, but somehow, Collabora doesn’t work.

Q2: What about my config could stop it from working, is it the certificates? the apache conf in general? the fqdn in docker?

Thank you in advance.

EDIT: Will add apache conf in 2nd post, apparently the link limit for new users doesn’t allow me to post it here.

apache conf