I've an airtel connection, it says the same on their airtel app that the phone needs a 5g support software update. But in reality it doesn't need any software update to run 5g if its available in your city. I'm running 5g airtel in delhi as you can look at my screenshots if you dont trust my words.
I don't know about Airtel so much because I'm a jio user and besides in the jio app it's that your device need to update to enable 5G. After consulting with my friends those are the Rog user just like me they said that they are also stuck on the same problem since the starting of last December. Nowadays on 4G the in-game ping goes upto 140-180 on the other hand my friends who are using 5G their ping goes upto 50-60. I'm getting a lot of problems because I'm a gamer.