Thanks for the drawing. It clarifies the old/new building situations. I have added labels to the buildings in your drawing. Could you tell me what's between the two red lines where I put a "?" mark and what are the four black boundaries by the blue arrows?
Looking back at your questions below, I don't think such automatic function exists in ArcGIS Pro (yet).
@Studenthas wrote:
Is there a function to compare two map layers to create a new layer. (details omitted here) (The function could therefore look at the new things that are on the newer layer.) Is there a function that 'automatically' wipes away the 'piece of land' that is under the new building? (White polygon or...).
To create a new layer or a feature class from two inconsistent layers may not be a straightforward task based on your drawing. I am still not clear about what you meant by "wipes away the 'piece of land' that is under the new building". May I ask you to post another drawing of what the expected result looks like?
You may need to do some analysis to get data organized to meet your expectations.