Really? Every installation I've seen with Lineage is to flash microG or MindTheGapps separately
I've used lineage for a few years now with only Magisk as an extra zip (no gapps) and I have not seen any google activity.
https://grapheneos.org/usage#sandboxed-google-play
I unfortunately can’t speak to what they mean by sandboxed Google Play being ‘close to fully functional’ as I haven’t used it yet.
I’ve also been trying to replace notification push servers for msg notifications as those are usually routed through Google services. This article has a short explanation of what I’m referring to: https://medium.com/@KaushalVasava/push-notification-in-andro...
Like others have mentioned, I was also referring to the connectivity checks as well. GrapheneOS maintains some servers to provide the same service which the Google equivalents do, just without actually talking to Google.