Expert WordPress Speed Optimization for Mobile Performance (Salient/WP Rocket/Cloudflare)

I am seeking a top-tier WordPress performance expert to solve a specific mobile speed issue on my live business website, www.gria.com.au. The site is built on a high-performance "best of breed" stack, and while desktop performance is nearly perfect, the mobile performance is unacceptably slow. Your task is to diagnose and implement a definitive, global fix to make the mobile site load as fast as the desktop version across all pages. This is a targeted optimization job, not a full website rebuild.

The Problem in Detail:
The core issue is a significant and consistent discrepancy between the site's desktop and mobile performance, as measured by Google PageSpeed Insights on July 22, 2025. This problem persists across different page types, from the complex homepage to simpler inner pages.

Reference 1: Homepage (/)
https://pagespeed.web.dev/analysis/https-www-gria-com-au/faa1phk3w0?form_factor=desktop

Desktop Performance: Score: 97, LCP: 1.2s

Mobile Performance: Score: 71, LCP: 7.1s

Reference 2: Contact Us Page (/contact-us/)
https://pagespeed.web.dev/analysis/https-www-gria-com-au-contact-us/ireiurcxz6?form_factor=mobile

Desktop Performance: Score: 99, LCP: 0.6s

Mobile Performance: Score: 69, LCP: 8.0s

The primary bottleneck identified by Google for the mobile version is "Render blocking requests", indicating a severe issue with how CSS is being loaded on mobile devices.

Required Technical Expertise:
The successful candidate must have deep, hands-on experience with every component of our specific technology stack. Please do not apply if you are not an expert in the following:

WordPress: Core architecture and best practices.

Salient Theme: Including its native performance options and how it handles header images (CSS background images).

WPBakery Page Builder: Understanding how it generates page structures.

WP Rocket: Expert-level knowledge of its advanced file optimization features (Remove Unused CSS, Load CSS Asynchronously, LazyLoad, Preloading) and how to configure them for complex themes.

Cloudflare: Deep understanding of the full proxy service, including CDN, Automatic Platform Optimization (APO), and specific settings like "Cache by Device Type".

Sucuri: Understanding how a Web Application Firewall (WAF) interacts with a CDN and caching layers.

Image Optimization: Knowledge of Imagify and the importance of properly sized responsive images.

Custom Code: Ability to diagnose and implement solutions using custom CSS and PHP (functions.php) when necessary.

Your Task & Desired Outcome:

Analyze the existing setup and performance reports.

Implement a definitive, stable, and global solution that resolves the mobile render-blocking issue across the entire website.

The primary success metrics are to reduce the mobile Largest Contentful Paint to mirror the excellent desktop performance:

Homepage LCP Goal: Under 1.5 seconds.

Contact Us Page LCP Goal: Under 1.0 second.

All other inner pages should see a similar, dramatic improvement.

The final solution must work harmoniously within the existing technology stack and not introduce new issues (like layout shifts).

To Apply:
Please begin your proposal with the word "GRIA" so I know you have read this description thoroughly. Briefly outline your initial hypothesis for the cause of this issue and the general strategy you would take to fix it.