I wanted to buy device wifi intercom for personal usage free spectrum , so any information on devices that already has an approved ETA so that the same can be bought without issues or kindly guide me in this matter on importing

Now you can get VHF band License Free Walkie Talkie (like FRS/GMRS in US), approved by Govt. Vertel is one of the brands. Just search for "Licence Free Walkie Talkie" , in Google . These are also available in local Electronics Components market in Bangalore. So they should be available in your city too

https://www.indiamart.com/proddetail/vertel-walkie-talkie-license-free-15024711155.html