Which Takes Precedence When Customizing?

I’m still working on customizing my site and with some help from other forum users have managed to figure out how to do most of what I want so far. But the process has raised an important question, at least for me…

It seems there are a number of ways to create customizations:
1 – using Elementor
2 – by going to the Appearance > Customize section
3 – by going to the Appearance > Theme Editor section (where one can edit the stylesheet)

It seems that in some cases, there is more than one way to approach a particular customization. In other cases, only one of these will work.

My question is, which takes priority? For example if I change the header background colour to 3 different colours using each of the 3 methods listed above, which one will override the others? Not that I mean to do this on purpose, but my point is I’m trying to understand where I should go first to make a particular customization. If what I want to do is not available there, where should I go next, etc?