Yeah I once looked around both Pashtun, Punjab reddit - basically places for ethno nationalist folks
I wouldn't call it "separatist"- Pashtun (pak+Afghan) reddit was filled with Afghan people shit talking Punjabis, against Pakistani nationalism but no one was looking for "separatism" even in a toxic place like that they were not talking about "separatism" at most people- "afghans" might talk about a autonomous province
More focused on Ethno nationalism
Punjab (mix of Indian,Pak Punjab) reddit is also about "punjabiyat" - A little less toxic but I have read some shit talk against Hindustani/Pashtun but not a lot - its mostly about promotion of Punjabi language, culture, traditions, history etc
I think OP is fearing it a little too much... normal in a multi ethnic country and the critical mistake is - Ethno nationalism =/ separatism
Different things
I don't want to look at Sindhi stuff though- I fear it...
Pak south is deep into ethno-nationalism
You should do more research into Indian ethno-nationalism than, you are wrong in my humble opinion ...