Why not think about the program you are working on as a program that is built to support the open standards that enable people to communicate and concentrate on performance within these standards?
If someone wrote a bad performing non standard compliant code the program should throw an error.
Making bad code run faster is overstepping the boundaries.
I've used Netscape then switched to Firefox when Netscape became way too bloated, then enjoyed years and years of Firefox getting better, supporting new JS and HTML5 features all WITHOUT telemetry and with the Crash Reporting window where I can see the data that is being submitted and submit it if I want to submit it.
What have changed so much in last 5 years or so that now you have to get all this data? What is wrong with just building a standarts compliant browser that runs JS fast and has easy to understand settings (where I don't have to go to about:config to disable the WebRTC/telemetry/Pocket etc) ?
Making bad code run faster is overstepping the boundaries.