A great way to understand a live protocol at a high level is to just transact with it in different ways (via the frontend), and then analyse the transaction trace on tenderly, or the blocksec explorer.
The vast majority of vulnerabilities are due to logical flaws or a lack of constraints and don't require a deep understanding of the EVM's inner workings. These are found by training your auditing skill through deliberate practice.
So in terms of technical knowledge, you can achieve great results if you just learn the basics thoroughly (e.g as much as teaches).
