next-session | Simple promise-based session middleware | Runtime Evironment library

2SXC 10.25.2 / DNN 9.3.2

I have a 2sxc module that uses a C# template with "list" enabled. I have a content type called "pathway" and inside that I have 2 entity picker fields for "first step sessions" and then "next step sessions". These entity pickers use a "session" content type. Inside each of those "session" content types I also have an entity picker for "speaker(s)". All in all, it's a setup that I have lists within lists within lists.

When I create the loops for each of the sublists, I can easily do that within the 1 C# template but it becomes repetitive, long, and unruly because there's so much c# code where I'm looping the same session template for different entity picker sections. So, I tried using the "Render sub-template" code to simplify the template - I created new sub templates and inserted them in - it seemed to work at first, however, the template started outputting all "session" items into each item in the list.

I suspect that the subtemplate somehow loses the context of the item that it's in so it's outputting everything. Is there something special I need to know about using subtemplates with for each loops? Do I have to include params and, if so, how do I do that?

EDIT to include code sample:

Here is a small, simplified version of the code I'm working with: