Browser extensions for web automation for Edge, Chrome, Firefox and Opera

I have an automation tool where I want to add browser automation (to automate clicks, element extraction etc). This automation tool is built in .NET and I have prepared a document of the methods needed and ways to communicate between extension and my software. This document is here:

https://docs.google.com/document/d/1S4JRa7UH92BbfNzDRRRrpScO_i9NAi_bkONFiGn9AuA/edit

I need 4 extensions developed;
* firefox
* edge
* chrome
* opera

What is important:
* security
* clean code
* speed