Retrieve all 30k photos transferred from iMac to iCloud. I find this produces more problems than worth file

Imac 5k 2tb Ventura . I thought that if I transferred all of prior years of my 30k photos from iMac to iCloud that I would reduce the load on iMac. I now find that this is cumbersome e.g. when you retrieve a photo from iCloud to Photos on Mac for say editing or printing. I have sufficient space on iMac to hold originals of my 30 k photos. How do I restore from iCloud and leave the photos safely in iCloud for use on iPhone and iPad? Would there be any duplication problems in the case of some photos having been already been transferred?