This was my same experience. I spent three solid work days trying to install it from source since it's on a server with other services and their default nginx etc. setup couldn't work. All the different microservices made installing from source very difficult. I ended up finally giving up and using the black box omnibus installation and fiddling with the configuration file for a while.

It works now but I can't hack the source to make custom improvements, so it ends up not being as open source as I would have hoped. There's one particular issue in trying to push that results from being on a URL subpath (http://.../gitlab). I can't fix it myself because of that.

Don't get me wrong--it's a good program and has worked for the team I support. But click and deploy is not useful for people who don't have bare bones servers they can spin up and instead have to work with shared servers.