iPhone 15 Pro shows hardware issue and mobile services greyed out after updating to iOS 18.4.1

I purchased my iphone 15 pro not even a year back and it was working fine till today morning but then as soon as i updated my ios to ios 18.4.1 version my mobile service setting greyed out and esim is not working at all and on diagnosis it shows there is an hardware issue ???!!!. I have not dropped my phone and never took it anywhere close to water. I am surprised by the fact that just before update it was working smooth and after getting updated it shows hardware issue ! And mobile services stopped working at all whereas the other features are working properly. I went to the apple service center they directly asked me to submit my phone without proper diagnosis and without giving me proper reason and ans to my questions. They asked me to pay 65000Rs (Indian currency) in order to fix the hardware issue. I have not even completed a year and why would i pay for something i have not caused! How the system shows hardware issue after getting updated ! I am so much disappointed today with the apple services and its software glitches! I won’t be sane until and unless i will get the proper answer. I have only one phone and when i asked the service centre to give me loan phone they straight away denied! It was extremely rude behaviour. All of this issue happening is affecting my mental health as well as my productivity as i have no cellular network !

[Re-Titled by Moderator]