It was a long tiring process wherein close to 2 days were gone trying multiple methods, flashing QPST roms around 10 times to observe network in Stock ROM, in Custom ROMs and after reflashing etc etc etc. I spent many hours searching for finding right steps. Even when I restored modified xqcn and got IMEIs back, it had only one sim actually working and other had no signal. But there were various posts and mixed feedbacks. The way out was to restore xqcn file and use it to get back IMEIs, mac address etc. Worried, I searched across internet to find out ways to restore IMEIs and get my phone working again. This left me with a phone having no IMEI, no mac for Wifi and Bluetooth. I accidentally restored TWRP backup of another Zuk Z2 phone on my new pgone and in this process over-wrote the EFS partition.