Yeah you can only use liquid in the Theme code. So you’ll have to do it in product.liquid, which probably points to a section file called product-template.liquid. What I would do is tag all of the products that you need to include this table in, something like “show table” – I assume you’re wanting to put it by your description. Let’s just say you are, in product-template.liquid in your sections folder you would Ctrl + F and search for “product.description”, you’ll probably find something like this:
{{ product.description }}
Underneath that you can check and see if your product contains the tag “show table” and then display that snippet if it does:
{{ product.description }}
{% if product.tags contains 'show table' %}
{% render 'my-table' %}
{% endif %}
Something like that. Let me know if you need help, I can request access to your themes and products and get it sorted out for you.