I can live with loudness, clunkiness and inefficiency too as long as it works reliably and lasts lifetime.
I do not think you can do much about those things with big straight cut steel gears, that's the price for robustness.
If you are looking for low maintenance and longevity you have to use the biggest diameter rotors (220mm or 223mm?) and calipers with biggest contact area brake pads with sintered metal compound. Magura quad piston calipers offer probably the biggest brake pads.
I would pick the same frame again because of this is the only frame offers such big battery, big motor and looks very good at the same time.
By the way I did not mentioned here but you have to apply Loctite SF7471 primer and Loctite thread locker (probably red is more suitable) on the rear...
There is Optibike with such power. It looks like pretty good 2500W emtb with its own motor. There are also good frames for Bafang m620 motor you can turn to 3000W and equip with good components. Some sells complete emtb bikes with unleashed m620 motor and good components like Watt Wagons or...
Let me guess, you rode it on chill or cold weather and parket it in a warm room and next day you can not actuate it? Mine PMW Loam dropper does the same (it looks like they all do this).
You have to cool the dropper down to unstuck it (bring it outside and let it seat for an hour). People...
If you are talking about this cell INR21700-M58T I did not know such thing exists. It was not even in the list of the battery cells where I purchased the cells. But it if it has capacity 5800mAh then you can make 1206Wh battery out of those using the stock case.