Get entries related to same category
If you have infoPage with category A and B lets say.

Then, you have a Product 1 with category A and B also.

If in your template you do (with entry being the current infoPage entry):

{% set relatedProducts = craft.entries.section('products').relatedTo(entry.relatedCat).all() %}

{% for relatedProduct in relatedProducts %}
    {{ relatedProduct.title }} &lt;br&gt;
{% endfor %}


You should not get Product 1 returned to you twice..? Have you actually tried?