EZiniT .

You said "The noise appears mostly on areas where I’m using a mask to blend different breakup/detail layers"
I think you could be onto something!

We covered some renderer settings and that doesn't seem to be an issue.

Tomas gave a great tip freezing one frame to help identify what could be wrong.....did you try that?

Personally I would remove everything at this point and try step by step adding it back, process of elimination
with very basic default settings.....pretty obvious advice but without a hip it's hard to give an accurate answer.

Activate ghost other objects in the viewport.

Right click the geometry select mode icon (left of viewport), turn on "double click to jump to other object"
this enables swapping between any ghosted and working objects with just a double click in scene view

Similar thing by right clicking over the ghosted object for the menu "geometry/selectable template".

Other than that Python is probably your way to go.

Are quickmarks what you are looking for?

1: Go to the node you want to focus on.....press CTRL + 1
2: Go to another node (any context).....press CTRL +2

Now all you need to do to swap between locations is press 1 or 2

There are 5 quickmarks in total available.