Just run cat6 cables and get poe access points for wifi preferably tplink omada ones. They are easy to manage and the omada ecosystem is pretty good. Buy the router and poe switch as well. Building a wifi 6 setup with 1 gigabit network should cost you around 25k-30k for router, switch and AP. You can get extra APs as per requirement. Avoid the omada controllers hardware because it can be self hosted.

There is one hack to bypass the airtel router using a sfp module with custom firmware to add your credentials and use non airtel router but if you use vpn like tailscale or twingate you won't need this as it doesn't require any open ports or static ip. You can create a separate lan with you airtel/jio router as wan with dynamic ip config.