Help to solve a Magento 2 problem with Varnish and Nginx

I'm developing a Magento 2.4.2 e-commerce with 220.000 products and 590.000 registered customers. I've migrated all data from Magento 1 to Magento 2.4.2 but now I have a problem with site speed because with Varnish pages are cached again for each person (the pages are unique to each person/connection). So if I load the home page twice on the same device the page is cached. But if I go to the home page on my phone the page needs to be cached again. I've tried a lot of solutions founded online but no one solve the problem. I'm looking for someone can solve it. Here all informations about Magento, extensions and server configuration: SERVER • Server Magento: AWS EC2 [login to view URL] • Server Varnish: AWS EC [login to view URL] • Server DB: AWS RDS [login to view URL] Attached you can find server configurations. MAGENTO 2 Template: Codazon Fastest - Hightech Attached you can find list of enabled modules.