It won't work that way because having Karachi decoupled from Sindh will result in a domino effect of ethnic separatism.
Karachi is big - but both Sindh and Pakistan are bigger.
You can hate on 'jagir dakoo' or whatever you keep talking about. The truth is that the province (including Karachi) is theirs and belongs to Sindh. You don't have to like it but that's how it is and that's how it will stand for centuries to come.
If it's their they would have taken care
Of it like how Peshawar, Lahore, Islamabad and even queeta is
which they clearly haven't as they left the people, city to rot because they're racists against people of Karachi and want them to suffer
It's used as a piggy bank to feed the whole of sindh as the rulling class failed to develop any other mode of revenue alongside DHA Mafia who steals it's real estate, criminal gangs and all sorts of nasty things
This money is used to bribe wadera dakoo shahi and the local people so they don't go out of line thus perpetuating this cycle
It doesn't belong to them- they didn't make any of it's institutions, don't run it's economy, simply lack the capability of running a big city nor have they made an effort to try
It can remain under Sindh like London is part of the UK but letting them govern Karachi can never be allowed
Ideally every big city should be like this but more so Karachi as it's a totally different ballgame to other big cities relationship with their provincial governments
Pakistan is bigger than the complaints of a bunch of privileged burger karachites
I'm a Lahori