Copy a large number of iCloud photos to PC

I would like to copy approx. 17,000 iCloud photos to my PC, then store them on an external drive so I can begin placing these into files. From what I am reading, the most efficent way to so this (vs. doing by 1,000's from iCloud photos in Windows) is to send a request to "privacy.apple" and they will send as a zip file. I was ready to do this, but before doing so I wanted to ensure these will be copies, and not removed from iCloud, and not lose any resoltion/size in the process. I sent an email to this group asking these questions and the reply was along the lines they only respond to priviacy/secutiry questions.

I appreciate your review and comments!