Upon Zero day CVE report from Google Zero team VoLTE has been disabled in Exynos 850 untill further notice for security reasons.

I bought an M12 so I was trying to estimate how it'll perform after 3 or 4 years. I think it would work fine for me. I don't generally use any heavy apps anyway, I just chose Samsung because of reliability in my Office like work environment

Chill mann, Exynos 9611 always had that problem

I'll say that you should update software or wait till airtel starts VoLTE in your area

VoLTE and ViLTE is dependent on area basis. I also had same problem with my older phone