Using RANKX on a subcategory that's part of a table variable

Hello,

I have a table that I am trying to create a rank measure for. The table columns I am need to rank is based on [Category], [SubCategory], [SalesAmount]. I found this article that related to my situation and tried:

Ranking by Sub Category =
RANKX (
    FILTER(
       ALL( 'Table'[Category], 'Table'[SubCategory] ),
      'Table'[Category] = MAX('Table'[Category])
    ),
 CALCULATE(SUM('Table'[SalesAmount]))
)

However, it did not work. So I am thinking it is because of the duplicates, so I go group them by [Category] and [SubCategory] with a SUM on [SalesAmount]. I accomplish this using SUMMARIZECOLUMNS(). However, the solution does not seem to work with table variables. It seems like ALL() does not accept table variables.

So may I ask how I can accomplish this?

The end-goal is to use the measure within another measure (or if possible be part of this whole measure I am creating) to find the rank of a subcategory, such that the table structure looks like:

[Category] || [Sum of SalesAmount for that specific subcategory] || [That Subcategory_Rank for Each Category]

For context, the category is a location, and the subcategory is a sales rep. Each sales rep may be found in all those locations. But I am focusing on just one sales rep’s performance, getting the rank for that person in each location.

Please and thank you.

EDIT: Apologies, I should have added that I cannot create a physical calculated table as base table is part of a SSAS and would prefer not to use DirectQuery if possible.