iCloud photos download

So I have a iPhone with about 48 thousand photos. Yes thousands. I think about 42 thousand of them are stored on my 200 gb of iCloud storage, thus filling up my iCloud completely. idk about the rest but I guess they’re just on regular phone storage. I want to move all my photos to “real” storage on a hard drive. I’m unable to download all my iCloud photos to my Mac because it only is a 256gb.

I haven’t found a way to make this work, any ideas?