Hi @constantinwp ,
This is Kate from PageFly, - Shopify Landing Page Builder App.
Your website is beautifully designed and elegant. It’s clear that you’ve put a lot of thought and effort into creating a great online presence.
From my experience, I noticed a few things that could be improved on your website:
1. Resize the header
You should resize the header, the sticky header takes up a lot of the space on the page. When customers scroll, it causes discomfort for them when viewing other content.
2. Highlight the Call to action button
The first 5-second impression is really important. Having a clear CTA button above the fold can encourage site visitors to take action.
3. Highlight product price
Locate and style the price so that it’s the most visible possible so that people can find it without effort.
Increase its visibility by using a large font size (similar in size to the product headline), bold text style, or eye-catching color.
4. Add “Add to cart” button to each product
An add-to-cart button is especially effective for visually-driven products that require little information to be bought. In these cases, an add-to-cart button allows people to quickly grab and checkout without being directed to many pages.
5. Add testimonial - customer reviews
Customer reviews are proof of your product quality. This section will help you build customers’ trust. You can show rating stars for each product or you can add customer reviews as text and photos.
Reviews are crucial when it comes to shopping online.
That’s all of my feedback. Hope it helps to increase your conversion rate.
Merry Christmas! Wishing you love and happiness this holiday season. 
Cheers,
Kate | PageFly team