That’s great @abella91! And thanks for sharing the configuration that made it work!
Just a side comment - I’m sure you are probably aware of this, but just in case others will be reading this thread: mounting the docker socket into the runners directly and executing user-defined CI jobs there is a potential security risk - you might want to consider a root-less image-building solution like kaniko (I’ve tried this and it works - see the gitlab documenation on how to set it up and this post about another renku deployment using it) or docker running in rootless mode (have not tried this).