If you are a home user or small business, or Microsoft 365 Family is cheaper and easier.
That ISO file is the "Office 2021 LTSC Professional Plus 16" that enterprises deploy. The internal version number is (or newer cumulative updates). microsoft office 2021 ltsc professional plus 16 link
Unlike Microsoft 365, Office LTSC 2021 provides a fixed set of features that remain consistent throughout its five-year support lifecycle. If you are a home user or small