Your announcement bar is wayyyyy too long. It should be for announcing a sale or your free shipping but not for writing a paragraph.
Remove your dynamic checkout buttons from product pages and remove the buy now button. You just want the add to cart button.
Change your add to cart button to a bright color.
Remove catalog from your menu and have the collections listed. I would probably have men’s sunglasses and women’s sunglasses as the two main collections and then below them you can put styles or allow people to filter them on the collections page.
Your shipping text on your cart is confusing. It says the item will ship in 2-7 business days. Does that mean you are waiting a week to ship the items? Do you mean the items will ARRIVE in 2-7 business days? If the latter then put your item will arrive at tour door in just 2-7 business days. I would also get a better average. If the majority of orders are 4-5 then put that in your announcement bar. FREE 4-5 day USA shipping!
There are many other things that need fixed but those changes will help you immensely. I would consider hiring someone on fiverr to give you further help with optimization ideas and strategies.