Merge, Add, Subtotal, Filter by User

S2 , I think you can unpivot the table and use that

https://radacad.com/pivot-and-unpivot-with-power-bi

Don't @S2,

According to your requirements, I tried one of the simplest methods, which can be used as a reference: create three measures to count the number of Author, CoAuthor1, and CoAuthor2 columns. Create another table and accumulate the obtained number.

Measure1 = 
CALCULATE(
    DISTINCTCOUNT('Table'[Report Types]),
    ALLEXCEPT('Table', 'Table'[Author])
)

Measure 2 = 
CALCULATE(
    DISTINCTCOUNT('Table'[Report Types]),
    ALLEXCEPT('Table', 'Table'[CoAuthor1]),
    FILTER( 'Table', [CoAuthor1] <> BLANK() )
)

Measure 3 = 
CALCULATE(
    DISTINCTCOUNT('Table'[Report Types]),
    ALLEXCEPT('Table', 'Table'[CoAuthor2]),
    FILTER( 'Table', [CoAuthor2] <> BLANK() )
)

Put the measurement in the table:

Create a new table and add the Sum_Author:

Table 2 = 
VAR t1 = 
SUMMARIZE(
    'Table', [Author],
    "R", [Measure1]
)
VAR t2 = 
SUMMARIZE(
    'Table', [CoAuthor1],
    "R", [Measure 2]
)
VAR t3 = 
SUMMARIZE(
    'Table', [CoAuthor2],
    "R", [Measure 3]
)
RETURN
UNION(
    t1, t2, t3
)

If the problem is not yet resolved, provide detailed information about the error and let me know immediately, waiting for your response.

Best regards
Henry

If this post helps,then consider Accepting it as the solution to help other members find it faster.