There’s already a project that looks a lot like yours. “We don’t need another one.” Of course, it isn’t, becuase your boss hasn’t seen what you have seen, but your boss has already signed off on the one that’s running.
Is that a reason to stop?
Communities of practice are not popular with the boss, precisely because the boss has a different point of view to you, the person working on the ground, talking to customers, and dealing with the day-to-day.
While knowledge transfer is an important feature of a community of practice, perhaps the biggest is that of listening and building support, if other people see what you see, then perhaps it’s worth pursuing. Even if the boss doesn’t like the idea, yet.