Slow to view iCloud Photos being synced

Are you saying that you have just turned on iCloud Photos syncing? Are you waiting to see the pictures appear at iCloud.com, on your phone, or where?

In general, Albums and pictures can appear at different times, and some pictures may appear before others.

Since syncing uses the battery, and since lots of people are very anxious about battery drain, the iPhone will avoid syncing when not plugged in. And since syncing uses processing power, and people hate slow downs, the iPhone will avoid syncing while you use it. And since syncing requires bandwidth, the iPhone will avoid syncing when the internet connection is weak.

So, if you want faster syncing, then find good wifi, plug the phone in, and leave it alone. All this applies to a lesser extent for a Mac.