I’m reluctant to call the things you’ve listed here “contributions”. They’re opinions about what should happen next in the software. You have numerous spaces to express these opinions, including but not limited to these forums, GitHub, direct email, and the conference.
I don’t mean this to sound antagonistic, but it sounds like what you’re really asking for is a way to compel other people to act on your opinions. The maintainers are inundated with opinions, including not least of all those held by their own client end-users.
If you want to contribute something useful, it has to move beyond one individual’s opinion. Build a working group. Write a design spec. Gather end user experience data. Operate at some kind of scale that goes beyond just having an opinion. There are so many ways forward to support this product, and in that process your voice will be clearer, more coherent, and more effective.