I think overall Google have been a force for good on the web - even if motivated by money - they've provided many free tools and support for webmasters.
google ads
I used to like GTM but if you want the tags to fire in checkout (you do) then you need to use the Shopify method of inserting the tracking tags. As of March Shopify finally support GA4 through the Google channel app. You can also use the Google app to
analytics
Rename similar events in Analytics to provide a clearer goal for Google Ads machine learning, resulting in better performance.
analytics
How to track form submissions using GA4 events properly, not just reading page views on a success page. If you don't use forms in an iframe then it's very easy!
As a webmaster, I am always on the lookout for new tools to help me in my work. Google provides a wealth of resources, and I am particularly fond of Data Studio for its ability to pull in data streams and create beautiful dashboards.