Is there any specific design or requirement that couldn’t be fulfilled by any Shopify theme?
If you are just looking for a specific feature, potentially you can get Claude to code it as an embeddable static html and just embed that specific part (using content editor in your page / blog).
Highly not recommend coding the whole page, or the whole site. Wherever / whoever gives you the idea to do this, maybe you should consult with them before going at it.