Wordpress WooCommerce Customization on Single Product Archive Page

Hello, I need help with some Wordpress theme customization. I wanted to add specific filters for each item that shows up on my product archive pages. Not all products will have the same filters, so I only want filters with items to show. Right now they all show regardless of if they are active or not. I played with the code a bit myself to create the new filters - not sure if I did it right. I need somebody to review what I did and set it up so that the filters only show if they are active.

Here is an example: https://joyinfusion.ca/product/miyuki-15-0-crystal-sliperit/
As you can see all the filters that show up on below the Add to Cart button should be there, however some items don't have a Coating Number while others don't have a finish for example in this product:
https://joyinfusion.ca/product/stormduo-copper/
I have to put NA for the finish.

As I have many more products to add, some of the filters will be completely different and the list will start to get long with lots of N/A.

ALSO

as you can see in the 3rd screenshot and the same as the link above - in the links on top of the image, the one before never works. I want people to be able to click on the category before where they are at to go back. Right now they have to click on the category before and the re-click on the category they were just in to get back to where they were.

Let me know if you have any questions! Thanks