WordPress Site Merge & WooCommerce Data Safekeep

I am looking for an experienced WordPress developer who can help me merge a newly developed WordPress website design into my existing live website without losing any current data.

Current Situation:

My live site is fully functional and has recent products, customers, and orders.

I have built a new version of the website with a fresh design, new theme, and new pages on a separate setup.

I want to copy the new design, theme settings, and pages into the live site, but keep all existing data intact — especially WooCommerce tables (products, customers, orders, settings, etc.).

What I Need:

Safe migration of the new design and pages to the live site.

Ensure no loss of existing WooCommerce data (orders, customers, products, coupons, etc.).

Fix any theme conflicts, plugin issues, or page builder problems that may come up during the merge.

Full backup and rollback plan before making any changes.

Smooth migration with minimal downtime.

Ideal Developer:

Strong expertise in WordPress + WooCommerce.

Experience handling database–level merges, staging-to-live migrations, and theme transitions.

Attention to detail and ability to work carefully with a live e-commerce site.

Deliverables:

New design fully implemented on the live site.

All existing data 100% preserved.

Post-migration testing for checkout, product pages, speed, and responsiveness.

If you have done similar migrations before, please share examples. I would like to get this done as soon as possible.