fix issues in react-native

hi
i have a website based on Magento 2, and by using its RESTful API's i have its Android & IOS apps built with React-Native.

Now, i want to optimize the search and product loading speed for our mobile app in 1-2 seconds. As its taking upto 7 seconds to load search results and products.

watch this video
https://drive.google.com/file/d/11QhKL34gnEhdcnCR9qNXNqQAH3UZjh2z/view?usp=sharing

RESTful API
https://www.istationery.com/rest/en/V1/search?searchCriteria[requestName]=quick_search_container&searchCriteria[filterGroups][0][filters][0][field]=search_term&searchCriteria[filterGroups][0][filters][0][value]=Acrylic &searchCriteria[filterGroups][0][filters][0][conditionType]=like&searchCriteria[filterGroups][1][filters][0][field]=visibility&searchCriteria[filterGroups][1][filters][0][value]=4&searchCriteria[filterGroups][1][filters][0][conditionType]=eq&searchCriteria[filterGroups][2][filters][0][field]=status&searchCriteria[filterGroups][2][filters][0][value]=1&searchCriteria[filterGroups][2][filters][0][conditionType]=eq&searchCriteria[pageSize]=10&searchCriteria[currentPage]=0&searchCriteria[filterGroups][5][filters][0][field]=website_id&searchCriteria[filterGroups][5][filters][0][value]=1&searchCriteria[filterGroups][5][filters][0][conditionType]=eq

Note:
i don't want any changes on website or its speed. Its just about optimization for mobile-app.