morapelor If a basic feature works on stock OS, but it does not in GOS, it is a bug. You can be as snide and snotty about it as you'd like, and you sure are and sure help yourself to it, but this is a very plain fact. If cellular calls did not work in GOS would you call that a feature request to make your phone be able to place telephone calls? That's your claim.
This analogy relies on a fundamental misunderstanding of what GrapheneOS is. GrapheneOS is not a "skin" of the stock Pixel OS but rather it is a hardened fork of AOSP.
To be clear on the distinction that further undermines this analogy: Cellular calls utilize standard GSM/LTE/NR telephony stacks that are part of the open source base. If those fail, it is indeed a bug because the core telephony code is broken. Meanwhile, RCS is a proprietary service run by Google that rides on top of the OS, heavily dependent on Play Services having invasive system-level privileges. On stock OS, Google grants itself those privileges by default. On GrapheneOS, Play Services is sandboxed like any other app.
When RCS fails because it can't access deep system APIs that GrapheneOS deliberately restricts for security, that is the security model working. It is not a "bug" that GrapheneOS prevents Google from reading your hardware identifiers. Making RCS work requires building complex, specific compatibility machinery to bypass these restrictions safely.
Claiming "it works on stock so it should work here" ignores the entire purpose of GrapheneOS. If you want stock behavior with stock privileges, you should use stock.