Clean reset without losing data?

Hello,

I have a problem with my WooCommerce website/shop, hosted by Hostinger. Indeed, it is too slow for my users. This one contains a lot of information that doesn’t exist anymore, i.e.: deleted plugins, changed themes, database that must be shielded… a lot of things that must cause problems and unnecessary overloads.

So I would be in the optics to put a big sweep in all that except that I don’t know how to proceed.

Roughly speaking : I want to start from a clean base of my site (new clean .htaccess, clean wp-config, …) without losing all my content (pages, plugin settings, customer accounts, blog posts, customer orders, …)

Is it possible to do this? And if yes, how?

Thank you !

The page I need help with: [log in to see the link]