Airtel offer fiber based broadband service all over India. Though Airtel gives wifi-5 dual band gigabit router but still you can feel some lag in the router if many devices are connected to the router at same time.
If you have a wifi 6 device and want to enjoy wifi-6 speeds within your device or if more than 10-15 devices are connected then we recommend you to use your own wifi 6 router. Have a look at few good Wifi 6 Routers for Airtel Fiber Broadband
However if you are facing coverage problem and happy with existing Airtel router then we recommend a good Wifi range extenders. If you want to upgrade the current existing router to wifi 6 and want to be future proof for any coverage required then we recommend mesh router system where you should start with 1piece or 2 pc wifi 6 mesh router system and can add more nodes in future.
In most case we recommend wifi 6 routers for broadband speeds plans of 300mbps or above.
For those on budget I would recommend Mercusys wifi 6 router which is a TP-Link sub brand.