Hi. Also few improvements (speed up rules) inside .htaccess should help a little bit.
Check also if your server supports LiteSpeed Cache - if yes, install free plugin for it.
Also consider using Advanced Module Manager (RegularLabs) to reduce number of modules loaded and displayed on mobile version only, make mobile version lighter than desktop one. For example, on smartphone people don't scroll down at the bottom so often as they does on desktop etc.
OR create mobile versions of some modules, with smaller images inside (but AMM is needed anyway).