Fixing our Magento 2.3.5 store - only above 4.8 stars review freelancers

Hello, We need to fix some problems within our magento 2.3.5 store. Bellow you can find them: - inactive configurable products that we cannot activate altought the stoc is above 0, they are assigned to the website, they are in stoc. - reduce the number of sql sleeping processes. 8 just stays there. - fixing layer navigation problem, selecting an attribute should show the products having that attribute instead display 0 results. Once deselected that attribute the site has an error. {"success":true,"html":{"products_list":" <div class=\"search results\"> <div class=\"toolbar-top\"> <div class=\"toolbar toolbar-products\" data-mage-init='{\"productListToolbarForm\":{\"mode\":\"product_list_mode\",\"direction\":\"product_list_dir\",\"order\":\"product_list_order\",\"limit\":\"product_list_limit\",\"modeDefault\":\"grid\",\"directionDefault\":\"desc\",\"orderDefault\":\"relevance\",\"limitDefault\":\"28\",\"url\":\"https:\\\/\ - change the design for some buttons on the checkout and cart. - regenerating links for active products in site, also for categories. - some of the product photos are not showing in the website, once i want to reimport it displays an error. If the name of the photo is changed then the photo is imported and applier to the product. Loading speed after changes should be better then now. We need to take this into consideration when doing changes. An experienced programer needed.