While the time and energy that went in the thread you linked is commendable, now is the best time to pack up all those tweaks and contribute them to the firefox-esr-mobile-config package in PureOS.
Everyone has that package already because it comes pre-installed with PureOS.
And the sole reason that package exists is to provide all necessary tweaks to make firefox-esr usable for everyone by default.
That way, all mobile PureOS users are going to benefit from it – not just those savvy enough and willing to copy snippets of code back and forth from a forum thread.