Both of Google's recommended methods of adding Analytics to a website load Google's JS library asynchronously[1]. Including it has no meaningful impact a site's time to first paint or interactivity.

There's a good argument to say loading 70Kb of JS you're not using is a bad idea, and if that's the case then your smaller script is an improvement, but there's also a good argument to say Google Analytics is powerful and useful and maybe you should be using the features that those 70Kb give you in order to improve you site in ways the user would notice. I guess it's down to your specific use case.

[1] https://developers.google.com/analytics/devguides/collection...