Yes, Google Photos does send it to the bin.
You can prevent this from happening by tapping the "Free up space" feature in Google Photos, which will delete all the photos on your phone that have already been backed up to Google Photos.
I found the reason in logcat while performing an backup:
BackupManagerService: Package com.android.chrome is key-value.
By default for abd backup keyvalue backups are disabled:
"/system/bin/bu" (the command that is called on-device by adb backup) help text:
-keyvalue|-nokeyvalue: include apps that perform key/value backups.
I don't know what tool you used for decompiling AndroidManifest.xml but both apktool and Jadx do not show an game_display_name:allowBackup=... entry.
No matter what allowBackup entries you have the only entry that matters is the one in the <application> tag. See Android documentation: https://developer.android.com/guide/topics/manifest/application-...