If you’re looking to keep your photos deleted on both Google Photos web and the Android app in sync, there are a few steps you can take. First, make sure that the same account is signed into both the web version and the Android app. Next, you’ll want to go to your settings in both the web and Android version of Google Photos. There you can make sure that “Backup & sync” is turned on - this will ensure that any changes you make synchronize across both versions. Finally, it’s a good idea to review the settings of your linked album (if applicable) as this can have an impact on the synchronization.
If, after making sure all of the above settings are good and you are still finding that your Google Photos web and Android app aren’t deleting the same photos, then the best choice may be to contact Google Photos Support for help. They should be able to troubleshoot any issues and get you back up and running!