can you upload photos from 2 different phones to same icloud account?

If you have iCloud Photos turned on in both phones and they are both using the same Apple ID for iCloud, they should both sync to iCloud (and to each other) -- i.e.) all of the photos should be on both phones and on iCloud.

Also see the following from Get help with iCloud Photos - Apple Support

You can see if a photo or video has uploaded to iCloud when you open the Photos app and view your library in Moments. Your upload status is at the bottom of the menu. You can also find photos and videos from your Photos Library that haven't been uploaded to iCloud in a smart album on your Mac.

If you have “iCloud photos”

turned on in both phones they should both send photos there, and share them back on the other phone

However it isnt clear if that is how they are “set to upload to iCloud”