Thanks for your review and your feature request! To be honest, the AMP thing is bugging myself a lot. However, the only way of solving the problem I can think of right now is checking every link on google whether it is a AMP link or not. And if it is, the extension would exchange the AMP link with a direct link. Given that the exension only loads once but the search results load whenever you reach the bottom of the page, this might be a tedious thing to implement or even impossible.
If you however know another way, I would really like to receive a pull request over at GitHub. Here's the repo: https://github.com/nitricware/Firefox-iOS-UA-on-Android