Splitting out items from a list to perform calculations

Is there a simply way to split out items in a field that is a “list of items” so that I can sum up the value of the items in that record? This is for an order summary screen for customers. I’ve searched this forum and others have had similar requirements yet seemingly much more complicated. Have I missed a way of doing this?

These screenshots should summarise my issue.
This is how orders are stored in my Database;
Screen Shot 2022-04-06 at 10.41.30

This is how I want to display them in a “My Orders” page that customers will access.
Screen Shot 2022-04-06 at 10.41.42

I can achieve displaying the lists in columns etc by using the “Split by” and Line-Break, it’s the calculations I’m having difficulty with. Can anyone suggest a way forward?