WordPress Site Fix and Rebuild

I'm looking for a skilled WordPress developer to fix errors on my current site and rebuild it for secure, logged-in access to essential industry-specific tools.

Requirements:
- Fix existing errors, notably the "Undefined array key" warning and others (total of 7 different errors).
- Rebuild site to include:
- Sizing systems tools (currently on the existing site)
- Product details
- Equipment submittals
- Equipment breakdowns for parts

Ideal Skills:
- Proficient in WordPress development
- Strong troubleshooting skills
- Experience with user authentication and secure logins
- Ability to create user-friendly, industry-specific tools

Please provide examples of similar work done.