It was powerful but confusing. The team writes,
Starting in July, new photos and videos from Drive won’t automatically show in Photos. Similarly, new photos and videos in Photos will not be added to the Photos folder in Drive. Photos and videos you delete in Drive will not be removed from Photos. Similarly, items you delete in Photos will not be removed from Drive. This change is designed to help prevent accidental deletion of items across products.
See also more detailed info as needed.
FWIW I bailed on this integration a long while back. Instead I now import images from my SLR & Insta360 to my Mac; edit/convert the selects to JPEG via Lightroom Classic & the Insta app; then drag the JPEGs into a photos.google.com in a browser window (so they’re grouped with my phone pics/vids); and finally back up the originals to an external HD. It’s not exactly elegant, but it’s simple enough and it works.