Internal network and trusted certificates with Collabora

Hi there.

Id like to know if there is a solution to nextcloud using Collabora within the internal network and removing the “not secure” notification on my browser.

Basically I have a Rpi4 running opensuse tumbleweed with docker, then nextcloud and Collabora.
My nextcloud instance Is behind an nginx proxy manager which is accessible though my domain “
Using the nextcloud instance is fine and the certificate is valid but I configured my nextcloud instance to use Collabora from my internal network

It works great but my chrome browser then complains about the website not being secure after opening a document with Collabora. Id just like to get rid of that.

I hope these screenshots make sense.