Can i connect with the CEO/Head of the apple for resolve the issue?

If you describe your issue here, then the other forum users can share their insights on that with you.

If you want to reach Apple, you need to contact them. The Community forums are frequented mostly by Apple users and customers.

The CEO of Apple does not do troubleshooting nor is it his job to.

Contact support for help with you issue.

Contact Apple for support and service - Apple Support

My issue is display flickering and slow response of phone day by day increase and after some time phone restart automatically

Depending on the model and age of the device, I think that display flickering may need hardware servicing. Do you have AppleCare+? That would make servicing much more affordable.

Slow response is likely a different issue, as it depend on details and expectations and apps. Is the disk almost full? How is the battery health? Where do you notice the slowness the most?

If someone suggested waiting for a software update, then that also depends on the exact model. Older iPhones may not get new updates anymore. (I’m not convinced that the issues that you mentioned are caused by software, or that software can remedy it. Software fixes are geared towards widespread common issues, often not the individual issues.)

What is the model iPhone? Identify your iPhone model - Apple Support

What is its version system software? Find the software version on your iPhone - Apple Support