If you go to the settings, there should be a notification category, which then contains another menu "App Notifications" where you can see all the apps that are

If you go to the settings, there should be a notification category, which then contains another menu "App Notifications" where you can see all the apps that are allowed to receive notifications, but I don't know if this will stop google play services to receive these identifiers. I use GrapheneOS, so I don't have any google play services running, but for the apps where I need notifications I use https://unifiedpush.org/ https://unifiedpush.org/ (only a few apps implement it) and I host my own https://ntfy.sh https://ntfy.sh server.