[robinj6]

This has frustrated me so much, as I spend a lot of time optimizing web performance. Gtag.js is pushed by analytics, however after loading it then async loads analytics.js. It is very inefficient, especially for sites that do not much more than track page views. It is the worst scoring factor on sites I optimize because there’s very little you can do about it without hacks.

[SquareWheel]

If you don't need any of the other features of GTag or GTM, you can omit them and just load analytics.js directly. It'll work fine and save you some data.

https://developers.google.com/analytics/devguides/collection...

I don't think this option exists with GA4, unfortunately.