Why is the assumption a conical grinder? If so the next step would be one with larger burrs than the current 68mm something substantial like 83mm. Other thought would be a manual grinder.
Thought about what I'd consider an ultimate grinder for home enthusiasts and came up with something like a singular unit/motor double sided with a flat burr on one side and a conical on the other that turns 180 on a turntable to face user pick. Ok maybe not feasible but a guy can have dreams.
Between order and chaos there is espresso.