I'd recommend to check for loading settings like are the JS getting loaded asynchronosly or defered, if you're using custom modules with images - do you use lazy loading and optimized size settings within the code, are the images uploaded web-optimized (in terms of file size)
Website not responsive according to WebSite Grader
Thank you Anton,
I know this tool but I was courius about this issue with responsive because it's the first time I see a website that doesn't pass it.
Can you give me some suggestion to deal with it without broking the website?
For the image, the first one is set "eager". Is there something more I could set?