My question is why Qualcomm while using the same arch, has not produced a chip as fast as the M1?
Apple designs chips and devices in lockstep. When designers were working on various A-series chips, they knew the details of the device, and could optimise on that.
Qualcomm doesn't get that kind of view. They make a generic CPU design for given market segment, and have to "please" much wider buyer range. As such, if they tried to apply some of the things that are publicly known about Apple designs, they would probably end up with a chip that would be hard to sell due to taking more space or having higher TDP etc. And before advent of multicore, Qualcomm was using the available space budget heavily to integrate the radio functionality internally (then it oscillated a bit over time depending on chip and market segment).