Can a 3kw rooftop system’s generation can generate differently the panels technology is different?

Yes. The solar panel technology namely-polycrystalline, mono-PERC and TOPCon can produce different quantum of power per day due to improved quality despite having the same wattages. So pick the latest technology to ensure the peak generation from your rooftop system. Out of all these, TOPCon produces highest solar generation, followed by mono-PERC and polycrtalline.