Audit Analytics: Data Science for the Accounting Profession (Westland, in the "UseR!" series) provides a very complete guide to these sorts of audit analytics problems. It would be a good investment for you. https://www.amazon.com/Audit-Analytics-Science-Accounting-Profession-ebook/dp/B08NYB2GCQ/ref=sr_1_5?dchild=1&keywords=audit+analytics&qid=1619490564&sr=8-5