Hi Edward,
We understand that you are interested in your website performance, but the request is outside of our support scope as the question is not related to our theme code.
In general, it is important to make the website load faster, and tools such as GT Metrix help you get more information, but the scoring is a little bit overhyped.
The best-case scenario is to use the common sense performance methods such as the ones mentioned in the article below:
The next step will be to avoid loading something that is not needed on a specific page. You can do that with a plugin like this one:
Finally, you can use plugins such as Autoptimize or WP Rocket to fine-tune the order of the styles and script loading and use their caching methods.
Honestly, limiting the Google Captcha script to only be used on the page that the form is will do the trick, I suggest that you do not go into the rabbit hole of deferring external assets of Google, for example, the Google analytics itself requires you to have it on the head of the code and then the Google page speed complains about that.
The other important thing to check is the First Byte load time which depends on the hosting service that you use.
Thank you.