In case it helps anyone: you can turn off issues in a GitLab project if you don’t want to see them.
But both for managers managing many top level projects, and for developers that are part of those (gitlab/yellow, gitlab/pink...)-gitlab falls down a bit on keeping things organized - it's hard to see if issues in yellow is keeping someone busy and so leaving issues hanging in pink.
We have the Analytics feature designed for that [1]. Please be aware of the distinction between Group-level and Project-level analytics described there.
If you have any feedback on how we can improve this feature, or if you have other ideas, please open an issue [2] and share as many details and examples as possible. We'd love to look into it!
Ideally with a filter on which projects to show.
This works for hierarchical structures today, but not across them. (I'm not sure the current data model is easy to bend into this, so it's understandable - it's just one of the few things we've seen that would let us to more of the project mgmnt in gitlab directly).