Thanks for providing this info.
I do use gitlab-ce at home for my personal projects and think it's awesome.
I would recommend it to work in terms of its features for code management and build pipelines.
But I just cannot see any of our product management team wanting to use this for Roadmap/Epic/Task tracking at all. Its far too technical and too close to the code, both of which are things they have neither the time, interest or skill to interact with. Management are comfortable with Jira (and some of the extended Atlassian suite), as it hides the technical stuff away and allows them to focus on the management data.
I don't know what the perfect solution looks like though, and I also haven't spend the time to exhaustively try all the competing products either.