I've basically lived my life inside issue tracking systems - it used to be JIRA, and I had built tooling allowing effective indexing/mirroring of JIRA issues, but then Atlassian decided to all but do away with on-prem users. So, like many others, I moved over to Gitlab instead.
As a product, Gitlab's great: it's got project lifecycle management, issue tracking, wiki support and even a container registry baked straight into it.
It's not just on-prem Gitlab either, it also affects their cloud offering.
Search within Gitlab is excellent, but this is of little use if you have things spread across systems and want to search from a single central point (to be fair to Gitlab, their idea is that everything you do should be within their solution, but life rarely actually works that way).
This documentation details how to use my new tooling (rudimentary as it currently is) to expose an indexable version of your Gitlab life. Although this is focused on an on-prem install, this tool should work with their cloud offering too, as the APIs are the same (but I haven't tested against it).