Help! Finding Photos based on date added to my iCloud photo library

My mother passed away about 3 weeks ago and the family is trying to save her photos. To do this, I used her phone and shared via Apple iMessage each year group of photos with myself. In other words: "2019 Photos". I then clicked the button that let me add each group to my personal library thinking I could put them all into their own folder as her pictures and then export them for the rest of the family on jump drives.

Unfortunately, this didn't work well because now all of her pictures are mixed with my own pictures in the photos app across 4 years!! I tried filtering by her phone model with a smart folder and some of them show up that way, but not all. What i really need to do is sort all the pictures by date added but I can't find this feature if it exists.

Any advice for me? I may have caused one heck of a mess here.