Sort by size

no

There are very limited sorting options - tell Apple your needs - https://www.apple.com/feedback/photos.html

for now just be patient and give it time (lots of time)

LN

The Photos app does not provide any way to do this that I am aware of. However, it is a virtual certainty that the largest files are videos, so selecting the "Videos" smart album & looking at the running time badges in the lower right of each video thumbnail should give you a good idea of which ones are the largest. If you have the Info window open, you can select the longest running ones one at a time & see their file sizes there.

My small 7000 item library (95 GB) took about ten days to upload

while the is no way to predict as there are far too many variables you could guess two to three days for yours

LN

Who knows? remember you can not sort by size

the finder tells me the library size - Photos and iCloud tell me the counts -no one tells me why

I am reporting my situation - if it is not helpful sorry

LN

joaopedrofdasilva wrote:

Is normal that it takes so much time to sync?

The time required depends on several different factors, but one of the major ones is your Internet upload speed. Many ISPs provide reasonably fast download speeds but much lower upload speeds. For instance, I get about 20 Mb/sec download performance but uploads run at only a little less than 2 Mb/sec. (The small b in Mb indicates bits, not bytes, so with overhead taken into account they are roughly 2 MB/sec download & a paltry 0.2 MB/sec upload!)

At those upload speeds, it could take weeks to upload a large library, which is why LarryHN said lots of time.