Do you have an example of your work? I'm curious what a report looks like, having done only a couple of 'code reviews' myself (that is, I got a codebase and three days to write a report on how it could be improved, not very formal at all).
The audit may encompass anything from code quality, technical debt, tech stack, architecture, infrastructure, to the product roadmap, licensing of dependencies, corporate structure, hiring/retention of talent, etc. It really just depends on what the company paying for the DD asks for (which could be either side, and that also matters a lot).
Each category in the final report will have a summary, a score, notes about risks/opportunities, suggestions on how to improve, what things are strengths, etc. It can be really, really long, and often it's broken up and worked on by multiple people based on their area(s) of expertise. Usually you'll see a high-level summary chart at the end of the report that just kind of puts everything in front of you.