If you're referring to your Shopify speed score, it's likely the decrease happened by installing more apps - that tool used the Google lighthouse API, a general performance analysis tool that doesn't score well for engaging ecommerce sites or correlate to actual speed in some cases. More about that here if you want details: https://speedboostr.com/shopify-speed-tool.
I recommend using an analysis tool specifically for Shopify sites. Here's one that my team built free for the community: Shopify Analyzer.
That will tell you what can and should be optimized on a Shopify site (based on data from thousands of Shopify sites we've optimized).
It also gives recommendations and resources to optimize in-house. Of course if you prefer to hire it out you can just contact us through the site.
Founder of
Speed Boostr (Shopify optimization experts, theme customization, custom app development).
Creator of
Shopify Analyzer (first performance analysis tool for Shopify sites, free for the Shopify community).
Creator of
Order Automator (auto tag orders and customers + auto fulfill orders + email notifications).
Creator of
Theme Scientist (A/B testing app) and
Tip Jar (add a tip button to your store).
