Airtel 2g is very good.
Airtel 4g/5g indoor issue, but will get 350+mbps speed when it connects to 5g at a very specific part of my home.
4g also network issue, but compared to all other operators its more reliable. Yesterday I just raised network complaint and immediately RSSI got increased and started connecting to 900MHz frequency within a minute and signal bar increased from 1 to 3 bars. Not sure it's temporary or permanent fix, since my ticket is open and assigned to an agent, being a black customer.
BSNL I had much hopes because of 700Mhz frequency for indoor. But it didn't work well as tower itself is too far or worst optimization. Need to check on 5G, but again the bandwidth which is allocated is not sufficient to serve large traffic and high speed, so no hopes.
Near my home VI store is present, hopefully if that also gives issue, they might resolve the complaint promptly.