NextJS Website Cleanup and Simplification

I need a seasoned developer to tidy up my NextJS website (hasn't been deployed yet but I can provide the source), which has approximately 330 files, excluding the node_modules folder. There are no DB connections. The goal is to transform it into a simple, maintainable site with a moderate level of theme simplicity.
Include "WySuiCleanup" in the proposal.

Key Responsibilities:
- Replace outdated themes with simple, yet functional, moderate-level themes while keeping the current layout structure intact.
- Clean up CSS where necessary and ensure it's efficient and effective.
- Update outdated packages, removing any that are obsolete. Preference will be given to packages with a minimum of 10,000 weekly downloads.
- Provide clear, concise instructions for local deployment and production deployment, potentially pointing to relevant websites for reference.
- Implement unit testing to ensure the reliability of the website components.

Skills and Experience:
- Strong proficiency in NextJS and website development.
- Experience with theme simplification and CSS cleanup.
- Familiarity with Tailwind CSS and its application in web development.
- Ability to update and manage software packages effectively.
- Excellent communication skills, particularly in providing clear instructions for technical processes.