Hello,
The low Rank Math score on the shop page is common because the default WooCommerce shop archive has little editable content.
Use a custom layout for the shop and add a custom text block above the products, targeting your main keyword.
After that, refresh the SEO score in Rank Math and check if it improves. If it still stays low, share a screenshot of the Rank Math analysis panel for the shop page so we can see which exact issues.
Best Regards