Is there an efficient technique to manipulate floors?

Hi

The quickest way is to just paint a new floor in, on a masked layer, then add reflections/highlights using layers set to multipy and screen respectively. Add a reflection for shine. I've lowered the opacity slightly to allow some faint marks to show (too clean looks false)

Dave

Using Photoshop layers you can replace anything you want.

Re: How to combine multi Psd Mockups with one script ?

I forgot to mention, you'll need a new background image to replace your current floor.  Look on Adobe Stock or other royalty free image houses.

Use Layer masks to remove unwanted areas from your image non-destructively.  Use a soft paintbrush with black to conceal or white to reveal.

How to use Layer Mask? Photoshop CC Tutorial for Beginners - YouTube