This is an accepted solution.
I like your sticky navbar
Recommend to add a CTA (Call To Action) to the main image section like "Shop Now" at all images like your "see details" also offer to writer there text that will cause the customers to go and shop at the linked page.
At this page https://jgcontemporary.art/collections/original-art
I recommend to make the price center and add also there a CTA button for each product
You did a great job on the product page
About the pop up make better one that will focus on the popup if you need help with the popup let me know