Reporting a review does not open a ticket you can watch. The report joins an assessment queue, is checked against Google's content policies, and a decision is applied to the review. In most cases there is no case number, no status page and no notification explaining the reasoning.
Because of that, published timeframes do not exist and estimates circulating online are inference rather than policy. What we can describe honestly is which characteristics tend to make a case move quickly and which tend to slow it down — and that is genuinely useful when you are deciding how to spend the next month.
It also means one thing to watch for commercially: if a provider guarantees removal by a particular date, they are guaranteeing a decision that only Google can make.