I’m wondering how related items section is working?
I don’t see any relation between the product, and the related items. They are not the same brand or the same category, etc…
In order to display related product add one and the same tag to the product group which you want to connect and show as “related”. In addition, enable the option to show related products in the Theme settings > Product page > show and hide elements
Make sure you have enabled the related products in the Theme Settings as I mentioned below.
If you still have the problem, please provide product page where related products are displayed incorrectly. I will check the settings and tell you what to change in the settings.