Uploading to both services is still supported through the Backup and Sync app. But once uploaded they are independent copies and deleting from one doesn't delete from the other. I also expect that this support will be deprecated at some point in the future.
Not keeping Drive and Photos in sync really killed it for me. I ended up switching from Google Drive to Dropbox but I still use Google Photos.
I have photos added to my library in Dropbox automatically added to my Google Photos library and this has worked well so far. [1]
I thought this was killed recently[1]
(this = google photos appearing in google drive)
Does it still work for you?
If yes, how? :)
[1] https://www.blog.google/products/photos/simplifying-google-p...