Is it possible to import existing images from an external disk without making a Copy? I don’t need a copy of something I already have stored on a disk. I only need to see them in Lightroom. Otherwise my storage space is used twice.
That's not the way Lightroom works. Everything you import into Lightroom is uploaded to a cloud server, essentially making a duplicate of what you have on the external drive. You may want to use Lightroom Classic instead. Lightroom Classic doesn't not make copies of your photos (unless you chose to do so for backup reasons). Lightroom Classic simply points to the location of the photos, whereever they are.