Looking back on my four experiences, English is generally more important in the assessment center, mainly self-introduction and some impromptu three-minute speeches. The assessment center is not an interview link used by every Big Four. But now I hear that the written part has been added, and English may also be tested. For the partner interview afterwards, if you are lucky, you may not need to speak English at all!
In short, practice some basic English: such as self-introduction, advantages and disadvantages, what I think is the most successful, what I think is the worst, and so on. The above is the most commonly used interview oral English. A considerable number of interviewers (as long as they are not foreigners) turn to Chinese after asking these questions in English.
Back to your question, if you don't get into the top four, you still have a good chance to get into a domestic firm. Now the system-related audit is a hot time, so we can consider it.
You can also choose the work related to internal control as your first choice in the enterprise. Secondly, it is good to engage in information system management according to your major, or simply accumulate some financial-related work experience, and you can transfer to internal audit more conveniently after 3 ~ 5 years. At this time, your two certificates are more effective.