I have no reason to believe at this time it's related to GrapheneOS itself - want to start off saying that.
My situation; I have Do Not Disturb on, with any contact that can bypass for calls. I have a Pixel 9a running the latest alpha GrapheneOS release and latest WhatsApp version. My issue, is that WhatsApp calls do not produce a ringtone like normal calls do. These issues can have various causes and are very specific to the user configuration. I have tried everything I could think off to fix it, but to no avail. I know this has worked in the past on my previous Pixel 7 also running GrapheneOS.
My question is if somone else has had this issue to, and if they know a fix or have suggestions for further testing.