Hi @Cheivi23
First, you need to know that customers are really hard to separate from their money 
And the store should calm them, give trust, show that it is safe to buy. Get them interested with a story, lead them, and offer a discount on their first purchase.
And I can not see that on your store, the big banner with a button that does not stick out. Then you have collections ( good) and products, and just 2 more sections: reassurance with icons that do not look good (like text from ChatGPT), and testimonials that are just text and can be passed (“Let customers speak for us” is not aligned and not clickable). So in all a bit basic and can be more. No mention of company/Our story/ more text for both customers and SEO. The collection page, so-so could use some filters, maybe, and more about brands. Product page again a bit basic, not enough sections and the product description not presented in the best way. Check MH40 Wireless Paris Saint-Germain for an example of a full page, a lot of info, that gets the customer hooked.
Now, checkout itself: a few things that can turn off customers but in general, think people just need some time to think, $200+ for a watch is affordable but still not a small amount. What I noticed that can turn off customers: colors are different the rest of the site. That green is not used before, so checkout looks like a different site, which can lead to uncertainty. In a page, you do not want uncertainty. The cart icon is different, too. I like to check contact/business information, and you do not show much initially. I did found on FAQ page just your info email. The Terms page has nothing. But then, on checkout, there are policies and legal which holds some data. Different email, address(city) from Spain, but in the FAQ I got the feeling it is US company. Note this, I think most people would skip but those who check can just be confusing.
The last thing to mention is your theme, Motion, it is a really old version and not sure why you did not upgrade. It is a version from December of 2018 and for more then 6 years them did have a lot of fixes, improvements, new sections, that can be useful and improve conversation.
Good luck, and I know you will get more advice from other members but also do a little research yourself here. Search for no sales, some tips repeat over and over, and can help you out.