I am looking for a way to get a count of projects filtered by Time or
Outline Codes.

I can get a count of all projects in the database using the following
formula. Count(descendants([Project List])) However, the number of
projects does not reflect the filter or or categories that I am
applying to the view (Chart).

You can use MS Excel PivotTable with datasource - project server database
and the following tables - MSP_View_Proj_Projects_Ent and according of your
project ouline codes -MSP_Cube_Enterprise_Project_Outline1,2,3.....