Doggy, thanks so much for the help, I finally got it working.

So thanks a lot for your patience, since I noticed early on that you like people to figure it out themselves ;)
This however doesn't always work like that, since not everybody will have the needed skills or level of experience, hence their question. All the comments you posted might be easily understood when one is already somewhat skilled in programming( a little bit more than novice level). I was/still am novice, that's why I posted.

That being said, thanks again. As I now (finally!) know what "the correct way to read or address the API data via what .NET command" is, I made a new script right away;

dim xml = API.XML()
dim DOGGYSTYLE as string = ""

dim x as new system.xml.xmldocument
x.loadxml(xml)

DOGGYSTYLE = (x.SelectSingleNode("//overlays//overlay[1]").InnerText)

If DOGGYSTYLE > 3 Then
API.Function("OverlayInput2In",Input:=1)
Else
API.Function("OverlayInput1In",Input:=1)
End If

You probably already know, but I've bound it to a (midi pad key) shortcut switches one of our cameras depending whether camera is shown in either overlay1 or overlay2.
Two other ones do the same for camera input 2 and 3. Now trying to make a single script out of it, instead of a seperate script for all 3 camera inputs.

Anyways, we all thought Doggystyle was a fitting name for the script ;P

Very true! It is hard to really explain what the situation is, and what the exact solution is you are looking for.

And yes, the script I was looking for was:

But since our first 3 inputs are always camera inputs AND I learned the proper way of connecting API with .NET (yes, I should've taken a better look at Scripting For Dummies!!), I wrote a second script (the one in my last post) that lets our Streamdeck switch to the corresponding camera (input 1, 2 or 3) whether at that moment it is showed in Overlay1 orrrr Overlay2 :)

Now we can go ahead for a few months haha...
Thanks again!