One of the major reasons of pti loss is TLP ambassador saga, they broke PTI votes ( especially in ramadan you dont go against the local mosques), along with giving ticket to an ordinary worker with no resources. Natural voters of constituency abstained from polls, those who participated were divided between PTI, MQM and Mustafa Kamal along with TLP. FAISAL VADA won last time with a razer thin margin because of his resources.
PPP broke into PTI pashtun votes in constituency by giving ticket to a pashtun heavy weight whereas with no recognizable name from pti, thats what got them across the line.
PLMN held on to its ethnic traditional votes in constituency and by giving ticket to someone with huge resources they were favourites to win but still lost.
This is not a typical constituency and has almost equal representation of all ethnicities, along with being a lower and lower middle class constituency candidates resources have a huge impact. Both ppp and plmn spent huge amounts.
This was both TLP and PLMN highest voter concentration constituency in Karachi ( probably plmn only constituency with high support, in rest of karachui they have negligible support apart from some isolated pockets), that is why shehbaz sharif stood from here in 2018. If they did not manage to win this constituency with a billionare candidate with pti at its weakest after TLP saga ( this constituency has high concertration of such votes ), it is safe to say they are not going to get support from karachi in future.
Unless pti forms a coalition with mqm and mustafa kamal, whatever pti looses ppp will gain. Coalition of pti and tlp was final in these elections before TLP saga.