I would like to decide for myself what the best optimisation and performance settings are. How can I override the autoselection of these settings?

Your current build of firefox runs substantially worse for me than previous versions. I use Firefox because it is non-chromium, which typically offers more user freedom and control, but these new performance settings which cannot be edited individually, but are controlled automatically, are overstepping. Please advise how I can change the settings on a deeper level than simply switching off hardware acceleration. I'd like to limit multiprocessing primarily, but I would also like to have access to other performance settings. Further, I would like to have more control over how Firefox can access my devices. Please advise how I can access and edit the full list of permissions available to Firefox. I ask for this in the interest of transparency and personal data protection.