Simple DAX Question

Hi all, first post in this sub. I have a PBI report that I’m building for a client and they have an extremely large dataset. One of their wants is to see 5 different metrics (parameter) by around 15 different view bys (a different parameter) using different time slices (a third parameter). This chart was one of the fastest to load in the entire report until they made it clear that they wanted a selectable top N filter. So if they wanted to see the top 3 lines they could do that but if they wanted the top 10 they could also do that. I created a parameter to control the top N selections and I cr