How to retrieve newObject by name?

how would I know which object in that
array i’m reffering to?

Loop through the children components and compare its names. If match - object found.

The following is pseudo code for a function to get a reference to the Child object:

   UObject* FindInParent(FString nameToFind){
        for each OBJ in YourParentObject->GetChildrenComponents(){
             if ToString(OBJ) == nameToFind{
                 return *OBJ
             }
        }
        return nullptr;
    }

Is this array a TMap where I can then
search it using the provided FName?

Yes, but it is Array, so you have to loop through it.

This is why I have a Tmap with names,
but this seems rather redundant.

This is not a bad approach, if that make sense to you. Personally, I like using TMap data structure in cases where it requires to access it frequently during the runtime.