to compress image use
Convert png, jpg to webp
https://convertio.co/jpg-webp/
Compress webp
https://imagecompressor.11zon.com/en/compress-webp/
Run these commands after enable merge and minify js, css from admin
bin/magento setup:upgrade
bin/magento indexer:reindex
bin/magento setup:static-content:deploy
bin/magento setup:di:compile
bin/magento deploy:mode:set production
bin/magento setup:static-content:deploy
Try to add a theme for Mobile and activate it from admin
Add a critical css from admin and deploy static content.
https://www.linode.com/docs/guides/build-nginx-with-pagespeed-from-source/
https://developers.google.com/speed/pagespeed/module
