Just for reference, this is what the Google Play services app transmits roughly every 20 minutes to Google if it has network access:

Phone #
SIM #
IMEI (world-wide unique device ID)
S/N of your device
WIFI MAC address
Android ID
Mail Address of your logged in Google account
IP address

And that is when you have disabled ALL telemetry in ALL of the options, even the most hidden ones. So this is the minimum amount this app is always gathering from every Android user using the Google Play services app, no matter what you selected. Other Google apps (like the Play store app) could then contain additional telemetry on top, this is just the common base of all Google proprietary apps. Or the minimum amount of privacy violations you get when using proprietary Google apps on your phone, no matter what.

If you use GrapheneOS, I'd recommend not installing/using ANY Google apps at all (not even Play store or Play services). To get apps, you should use (roughly in this order of priority): 1.) GrapheneOS's app store for the built-in apps 2.) Accrescent app store (has several good open source apps, is intended to be more secure than F-Droid) 3.) Obtainium (for getting open source apps directly from their source repos) or if you really can't get into Obtainium, use F-Droid instead 4.) Aurora Store (for getting apps from the Google Play store without sending too much data to Google. Only do this if there is no open source app available for doing the same thing).

To fully mitigate the removal of the Play services app, you also should probably install/configure a UnifiedPush client like ntfy to get battery efficient push notifications and ideally use apps which also make use of that, e.g. the Molly fork instead of Signal. It's quite easy to do, just something to be aware of. Then you're also independent from Google's push notification infrastructure (which is called "Firebase Cloud Messaging" (FCM)). But you need a UnifiedPush server to go along with it, either self-hosted or use a public one. There are some privacy friendly ones public ones out there. If you don't use Google's FCM and also no alternative like UnifiedPush, then app notifications will most of the time still work but will put an additional strain on your battery.