The way it's going, by the time the Motorola + GrapheneOS phone is out, it will be a lot more painful to use GrapheneOS than today. Not because of GrapheneOS of course, but because everybody accepts that bullshit Google is doing.
If you're waiting for Motorola + GrapheneOS, you could start complaining to banks and other apps that don't support GrapheneOS :-). If enough people did that, maybe those companies would consider it.
In the meantime, I'm currently using a low end Motorola moto g 5G 2023 which lets me turn off Play Services. Chrome and the Google Calendar don't run (really do need to find a replacement calendar), and I couldn't be happier. Motorola's interest in GrapheneOS makes me wonder if they did this on purpose.
Calendar server: https://radicale.org/v3.html Sync: https://manual.davx5.com/
So, you run Radicale server, you can import Google Calendar.
Set up Davx5 on mobile to sync with the local server
Access from anywhere with Tailscale.