Dual Sim drops Network signal

I have a dual sim setup on my iphone 13 pro max both on Airtel in India. Personal sim is an eSIM and the Office phone number is a physical sim. Whenever i turn on both the sims together, initially the network strength stays good at mostly full but slowly in a couple of minutes both the sims loose network and reach the lowest signal strength. 4G stops working on either sims even if i switch. Any probable resons/ fix for this issue? Because initially the network strength is perfect and the Network provider website also shows good strength in my area.