What's the best way to trace all the changes I've made to my system files over the years?

As I imagine a lot of Linux users do, over the years I've followed the advice of countless different threads, blogposts, videos etc. and made various changes to system files in order to improve my setup. Some of those were motivated by personal preferences and customisations, e.g. changing/modifying keyboard layouts or mouse settings. Others were more fix-oriented, such as fixing my laptop not being able to wake up from sleep due to some manufacturer-specific issue, or messing with audio driver configs to get audio to work properly. I now want to start over with a fresh installation. I'm planning to use the same distribution, and the same laptop, so most likely I will need to make those changes again to get things working the way I want them to - or even to get them working at all. Is there a **smart** way to go about figuring out what changes I've made over the years that I will likely need to remake after reinstalling? I've thought about checking to see which system files have been manually edited by me (assuming that it's possible), or even doing a diff on specific folders between my installation and a vanilla one. However, I definitely don't remember most of the files I've had to edit, and I don't know enough about Linux to know which files/directories are the important ones, which ones I can safely ignore etc. EDIT: To clarify, I'm not talking about dotfiles; I keep those under version control. EDIT 2: The distribution in question is Manjaro, i3wm version.