Website Functionality Enhancement

I'm seeking an experienced web developer to urgently improve the functionality of my existing website. The site is currently live but has several issues that need to be addressed to ensure a smoother user experience.

Key Requirements:
- Identify and fix bugs
- Improve site speed and performance
- Enhance navigation and user interface
- Ensure mobile responsiveness
- Implement any necessary security updates

Ideal Skills and Experience:
- Proven experience in web development and functionality improvement
- Webrtc

Please provide examples of similar work done and a brief outline of your approach.