Can't find a way to use CMS field in the Collection List in Custom Attributes parameter

I have a Collection List Wrapper element on the Pricing page, that is linked to Plans table in Ecommerce. The list extracts all plan details from that table. For each plan section there’s a Buy button.

I need to assign specific custom attribute to the “Buy” button for each plan. I have the required values set in the Plans table. But I am unable to link that value in the Custom Attributes section for the button element.
Tried setting up parameter name using {{parameter}}, doesn’t work. And there’s no “purple dot” near the “Value” field in Custom Attributes settings, that would allow me to choose the parameter inside.

Out of ideas at this point, please help!

Here is my site Read-Only:

Hey Denis, yep, I have that same frustration with e-com.

The technique I use for clients is setup a special embed inside of the collection item / page for the item I want to affect, and then I pull the data there using + add field references.

Script then has to do the reconciliation and apply that data as DOM transformation - in your case, setting attributes on specific elements.

There are a lot of ways to do the referencing but I find it easiest to use the embed itself as the point of reference, and then my selectors for what I’m changing are relative to that embed element. This makes it easier to operate inside of collection lists… sibling buttons, container links, etc. parent DIVs, etc. are all referenceable.