Since you have a firefox section and your stated goal includes hardening consider:
https://github.com/yokoffing/Betterfox
https://github.com/arkenfox/user.js
Floorp, an aggressively performance tweaked build of firefox, integrates yokoffing choices into its settings ui. These are each a file to drop into user profile and not for the faint of heart.
Since you have a firefox section and your stated goal includes hardening consider:
https://github.com/yokoffing/Betterfox
https://github.com/arkenfox/user.js
Floorp, an aggressively performance tweaked build of firefox, integrates yokoffing choices into its settings ui. These are each a file to drop into user profile and not for the faint of heart.