Nexus 3 Docker Registry behind Traefik v.2

Hey there, I have a similar problem to the one described here:

with the difference that I'm using Nexus3 as a docker registry (therefore I cannot apply the solution proposed in the post).

My problem is described in details in this post on stack overflow:

Any ideas how to solve it?

There is guidance from sonartype on running behind a reverse proxy.

https://help.sonatype.com/repomanager3/installation/run-behind-a-reverse-proxy
https://help.sonatype.com/repomanager3/system-configuration/capabilities/base-url-capability

I came across the documentation, however, I have no problem running nexus as such behind the traefik. I can fetch from and deploy to maven repo (same server, different port), I can also login to the nexus docker registry. The problem appears when I try to push into it.
The mentioned documentation unfortunately only covers httpd and nginx.
Don't quite understand would be the use of the base url capability mentioned in the second link.