GrapheneOS, as it ships, is rather bleak but you also need to consider that it is addressing the concerns of a very broad audience. That ranges from people who want to completely get rid of data leaking apps to those who want the apps but expect them to be sandboxed. Shipping two different versions won't really help them. It would only make more work on their end, with the results only reflecting two extremes. You are going to have some people willing to put up with some apps, but not others. You are going to have some people wanting some of those apps feeding fake data, but not others.
It's probably best to think of GrapheneOS as a base system that you build up to serve your personal needs, rather than thinking of them shipping it in a "perfect" state. While a handful of people will be happy with it in its default state, many will install something like F-Droid along with a collection of privacy preserving apps. Many others will install the Google Play Store along with a personally curated list of apps that reflect their needs, providing or denying access to their data as they see fit.
I believe the "build up" approach is the only viable way to handle this situation since we are talking about a group of users who are actively seeking out a third-party OS since they are particular about their needs. This isn't the typical consumer who will (gleefully or begrudgingly) put up with whatever the device vendor feeds them.