Hi @Ahimasho ,
The suggestions from Google PSI are, just suggestions so I wouldn’t make them gospel. Especially the unused JS recommendation, as the tool is not smart enough to know if the javascript is unused across the whole site. The best option is to manually go through the theme.liquid file and remove scripts that you are not using or hire someone to do this for you.
To help you, I ran https://shopmoonstone.co.uk/ through some speed tests and it loads in ~2.5 seconds with average internet connection in US, which isn’t too bad. However 2 seconds is the sweet spot.
I did notice that the lazy loading is being applied to the hero banner on page load. Images that appear in the users viewport on page load shouldn’t not be lazy loaded,as the browser needs to unnecessarily wait until it parse the lazysizes scripts, requests 1x1 image and then load the full size image . We have a guide on lazy loading here.
Also some of your images are very large in file size e.g. this image is 512KB https://cdn.shopify.com/s/files/1/0474/4229/6982/files/IMG_0699_1200x.progressive.jpg?v=1621871188. Maybe compressing and using normal JPG since you are already lazy loading this image.
Lastly I did notice you have your images named .png.jpg. I think just choosing one file format will be better. PNG should be for high quality images, and JPG for images you want to load quickly and don’t mind loss in quality.
Feel free to reach out!
eStoreSpeedOptimization