GA4 measures everything as events e.g. page view, click, form submission, video play, page scroll everything. So, its important to know how to set tracking for events in such a way that there is nothing missed, and nothing is duplicated. Here is the checklist for you:

GTM is a powerful and the most crucial component of connecting your website with Google Analytics. To capture right data, every GTM setup must have these tags firing on right pages.