I would be interested in working with you on this. I tend to agree that the theme needs to be updated. However, you can go from where you are to a cleaner look by keeping your existing theme. The scale of the work would depend on what exactly you want done. There are other issues as well. I ran an audit in Chrome and I am attaching the results here. You will want to speed up your load times to help with your SEO results. Most of that can be fixed with image optimizations.
Regardless, I do think that I could accomplish what you want to on a modest budget. I am a US based developer and I do quite a bit of Shopify development. If you are interested in working with me, send me an email: firstname.lastname@example.org
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hope that helps for you!