Website Audit & UI Revamp

I want to give our site a clear, modern feel, but before touching a single pixel I need a concise diagnosis of what currently holds us back. That audit should cover performance, accessibility, SEO signals, and, above all, user-flow friction points... (Budget: $30 - $250 AUD, Jobs: Graphic Design, HTML, PHP, SEO, UI / User Interface, Web Design, Web Development, Website Design)