50-Page WordPress Theme Rebuild

My current site runs about 50 pages on a Nicepage-based theme, and the extra weight is starting to show. I want every one of those pages rebuilt inside a clean, lightweight WordPress theme that delivers a modern, minimalist look while keeping all existing content, URLs, Custom HTML and SEO settings improved and intact.

The essentials
• Visual style: Modern and Minimalist—ample white space, crisp typography, zero clutter.
• Platform: WordPress only. I’m fine with GeneratePress, Kadence, Astra, Blocksy, a custom child theme, or a Gutenberg-first approach—anything fast and future-proof that avoids the lock-in problems I have now.
• Functionality to keep: simple contact forms that email submissions to me. No blog or e-commerce needed right now.

Deliverables
• New theme installed on a staging copy of the site
• All 50 pages faithfully rebuilt, mobile-responsive, and visually improved
• Contact forms recreated and fully tested
• Final migration to the live server with no downtime, broken links, or missing assets

Acceptance criteria include clean code, solid PageSpeed scores, cross-browser responsiveness, and seamless form delivery. Share a realistic timeline and links to minimalist WordPress builds you’ve completed so I can see your approach.