Hello! I am overstocked in certain sizes, and I want to run a flash sale. I am trying to create a collection where you can see only certain product variants (e.g., all T-shirts size 3x+). However, it appears that I can only add products, not variants, to a collection. Is that correct? I know I can split my products up in regular and large sizes, then add the large sizes product to a collection, but that's messy for a lot of reasons :(. Any help or troubleshooting ideas are appreciated.
This is a super late response and I'm not a professional at all but this is how I solved this same issue. I wanted to have a collection only show 3 colors of my products so I did this:
I created an automatic collection and for the criteria/ conditions, I said that the Variant's title must contain the name of one of the 3 colors. So maybe you could do variant's title must contain 3X, 4X, etc. This is the only way I've found to show only certain variants of a product in a collection