We are facing a similar issue with our website's Organic Traffic. The main reason is now Google is now more focusing on Core Web Vitals. These Core Web Vitals are directly affecting Ranking & Organic visits. Therefore, Kindly also check your Core Web Vital issues in Search Console.
**Follow these path to find Core Web Vital Issues: **Login Google Search Console -> Enhancement -> Core Web Vitals
I have already created one thread for help https://moz.com/community/q/how-can-i-solve-core-web-vital-issues-for-mobile-desktop
Edit: ReadManga.fun
