WordPress Revamp for Personal Website

I have a personal website on WordPress, hosted at IONOS. I wanted to improve its design, so I hired a developer to update it. Instead of modifying the WordPress site, that developer rebuilt the entire project from scratch as a React and Node.js application and deployed it on Vercel. The visual result is fine, but the setup is wrong for me: it forces dependency on external infrastructure, adds recurring costs, and means I cannot publish or edit anything without a developer. I want everything to live inside my existing IONOS WordPress install so I can manage the site myself, without learning new platforms and without paying for additional services. What I need is for someone to take the design and functionality already built on the Vercel reference and recreate it as a proper WordPress site on my IONOS hosting. Current website is oswaldosmarrelli.com.
Finally, I need a publishing guide in Spanish that explains how I can add articles, assign categories, and update sections on my own, without depending on a developer for routine changes.
The candidate must have strong WordPress experience and should include two or three live links to WordPress sites they have built. CSS skills need to be strong enough to match the reference precisely, and Spanish proficiency must be high enough to handle article content and write the publishing guide in Spanish, not through machine translation.

Please do not propose React, Next.js, Vue, or any JavaScript framework that requires external hosting. Do not propose Vercel, Netlify, a VPS, or anything that adds a monthly cost on top of my existing IONOS plan. Do not propose a headless CMS, hybrid stack, or any setup that would require me to manage a second platform. Proposals that include any of these will be declined immediately.