How do I fix calling and video playback issues on my iPhone 14 Pro?

I am using a iPhone 14pro which i am using since may 2023.

After just 1 year of purchase ans after warranty ended i started facing issues in my device.

The phone would get overheated and shutdown and randomly the earpiece speaker won’t work during calls.

Now after another year, the speaker snd microphone is also not working during calls

Youtube and instagram keeps lagging

Now i have also realised that siri , most apps and even trying to switch off device is lagging.

Have tried restarting device multiple times but to no resolution. Even the Apple Support Centre folks were not able to identify the issues.

This is making my first experience with Apple ecosystem a nightmare and making me want to switch out of it.

Has anyone faced anything similar?

[Re-Titled by Moderator]