Resolve PrestaShop Back Office Performance

I'm experiencing performance issues with my PrestaShop back office, specifically in the product management section ( for many task, changing just a word in product description,.. then when i register it take very long time). It is not recent module, not the server but we think there is an ajax code that créate the trouble

Also the front office is some time slow.
Ideal candidates for this project should:
- Have extensive experience with PrestaShop
- Possess strong skills in performance optimization
- Be capable of diagnosing and fixing backend and frontend speed issues.

Please provide examples of previous work related to PrestaShop optimization.