My Prestashop is slow
Theme performance level is on same level as default theme. It follows all prestashop recomendations about cache etc. Speed issues, assets loads etc are not theme related and they are not covered by support.
You can check following articles to solve some problems https://canonicalized.com/prestashop-speed-optimization/?section=prestashop-performance-options
You can get good or even exelent results with theme(as example check demo of page hosted on cheap shared hosting with lite speed cache)
It have very high 99/100 score for desktop and 80+ for mobile which is really high for software like prestashop.