aaravchen Yeah, I don't think setting READ_DEVICE_IDENTIFIERS to allow for Play Services is a security risk, but it may have privacy implications. It would be nice if someone could clarify what the issues there may or may not be.
As you say, I also understood that with Play Services installed, Messages should be getting this permission anyway. And I had the phone and SMS permissions set as you describe. But for whatever reason, it did seem like for me, when I set READ_DEVICE_IDENTIFIERS to allow for Play Services using adb that solved the 36 hour reset problem, as well as allowing me to get 20241120_00_RC07 to provision Etouffee to "true" which it wouldn't before. So I don't know if it was working the way it was supposed to.
This bug report seems to be addressing this issue, although there is also more to it: https://github.com/GrapheneOS/os-issue-tracker/issues/6331. Although, interestingly the issue was closed four days ago, with the original author of the report saying the problem went away for some unexplained reason. They are not in the U.S., but don't state what carrier they are on.
More significantly, for many of us, two days ago, it looks like they started adding some code to Graphene that may solve the problem on T-Mobile: https://github.com/GrapheneOS/platform_packages_modules_Permission/pull/84. The code would add a toggle for users to allow Play Services to do the verification it needs to do for RCS. So, there may finally be light at the end of the tunnel.