Collection sorting function

[Nardu_M]

Hi,
I'm looking to modify the sort by functionality on collection pages on Dawn v 10.0.0
the app used is the Shopify built Search and Discovery app

Our store's sort by price is not working correctly, as it seems to be taking the least expensive variant to sort by.
I've modified the price.liquid snippet to display the highest variant price on collection pages, and need this to be used to sort by.

In main-collection-product-grid.liquid there is a reference made to facets - {%render 'facets' %}, but I can't find where the actual logic is for the sorting and have looked in facets.liquid and facets.js files.

If anyone can point out where the code sits to modify the sort function, I really would appreciate any help.