Keep trying. Try different methods. What works for me debugging and refactoring distributed systems may not work for you. The thing I tend to drive toward is a single page mind-map-like artifact that is monotonically increasing in density with a focus on system-of-record and data flow. I tend to keep notes about individual tech and important systems in whatever tools are handy, either locally or in a form that are accessible to the team. Often this takes the form of a JIRA page per topic, or an nvAlt note per topic. Tickets aren't great for this because they are ephemeral. These notes are where code snippets, error messages, anything searchable, go. I have something like the Zettlekasten[1] method in the back of my mind when deciding on scope of these support notes. However I may also start from a simple local text file, not committed to the repository, or even attached as a note to a ticket or other ephemeral trigger. But the thing that ties it all together, for me, is that mind map. Once I have that I can truly reason about the system.

1 - https://zettelkasten.de/introduction/