If you are using iCloud Photos and My Photo Stream together on a Mac, you will not be seeing a my Photo Stream album at all. The My Photo Stream photos will appear in "All Photos" instead. It is much safer to use only My Photo Stream or iCloud Photos, but not both together. My Photo Stream is very limited and cannot transfer videos or Life Photos or the HEIC Photos taken on modern iPhones and iPads. To be able to transfer all image and video formats, it will be less trouble to use only iCloud Photos on all your devices. Otherwise you will have to download the missing items manually from your iPad and risk to create duplicates.
See: About iCloud Photos and My Photo Stream - Apple Support
My Photo Stream is yesterday's snow. apple has not added support for the more modern image and video formats, and for man years Apple is now showing this caution in all My Photo Stream document: "If you recently created your Apple ID, My Photo Stream might not be available. Use iCloud Photos to keep your photos and videos in iCloud." Users with a new AppleID cannot even activate My Photo Stream any longer.