ikariwths What is the fastest way to inform the developers about its importance? Do the grapheneos developers have a page where we can ask for future features?
It is possible to file a feature-request issue on the GrapheneOS issue tracker. However, personally I suspect the developers will not add this feature. GrapheneOS is focused on security and privacy, which consumes most of the development resources, and does not make a lot of UI enhancements. Maintaining and testing changes while quickly adopting upstream changes is laborious for even small changes.
ikariwths With this option when you call someone you don't need to hold the phone to your ear until they answer.
I sometimes use the speakerphone button in such a situation. And, again, it is possible that third-party dialer apps may have the feature you are looking for.