Speaking about performance, hosted Shopify sites score notoriously bad on performance metrics such as Google's Lighthouse Performance. I see many Shopify stores with performance score as low as 5/100. This lack of performance is hurting more and more the SEO and the traffic of those sites.
If you want to achieve higher score you will need host the frontend of your store on another platform like Netlify. I found the best solution to reach 100/100 scores is to use a JAMstack static site generator like Gridsome. Using a Gridsome powered Progressive Web App significantly decreases latency while improving discoverability.
As an expert in headless ecommerce, please feel free to ask me any questions concerning performance issues with Shopify stores.