There's already the Redirect AMP to HTML extension, I use it for both Firefox & Chrome
- https://addons.mozilla.org/en-US/firefox/addon/amp2html/ - https://chrome.google.com/webstore/detail/redirect-amp-to-ht...
- https://addons.mozilla.org/en-US/firefox/addon/amp2html/ - https://chrome.google.com/webstore/detail/redirect-amp-to-ht...
It's the plain fact that if this were a problem on Windows or linux, a free script would be available, but because it's Apple, it's a paid plugin or add-on, as it is with everything you need to customise an apple device.
It's a matter of developer culture, where you develop things for a fun, and to solve a problem. Not to make a quick buck.