Thank you for your answer, certainly I will test tinypng. Meanwhile I found out why I have 5MB of JS script, it is because of Youtube. I have a testimonial sections with 10 YouTube videos. I used the Webflow YouTube feature initially then I test using the Lightboxes.
Now I have 646.7 KB and a speed load under 1s without touching the images.
Now, I’m not a big fan of lightboxes, I’d rather use embed YouTube videos but I wonder if there is a script I can use to stop loading YouTube videos before the user clicks on them.