Sum Columns based on Column Header in a SUMIFS formula

I'm trying to create a dashboard.

=IF(AND(Dashboard!G11="All", Dashboard!G18<>"All"), SUMIFS(INDEX(dtPages!C2:R,0,MATCH(Dashboard!G18,dtPages!C1:R1,0)), dtPages!T:T,Dashboard!X11,dtPages!U:U,Dashboard!X13), "SOMETHING")

This formula is supposed to SUMIFS a column whose header is equal to cell Dashboard!G18 based on some extra criteria.
I get an "Array arguments to SUMIFS are of different size" error. I understand what the error means, and I suspect that it's this that's causing it:

INDEX(dtPages!C2:R,0,MATCH(Dashboard!G18,dtPages!C1:R1,0))

Which is supposed to be part of this formula (I assumed that you can leave out the "SUM(" part, given that the SUMIFS should calculate the SUM.

SUM(INDEX(dtPages!C2:R,0,MATCH(Dashboard!G18,dtPages!C1:R1,0)))

Can anyone help?

I've also tried:

=IF(AND(Dashboard!G11="All", Dashboard!G18<>"All"), SUMIFS(SUMPRODUCT((dtPages!C2:R)*(dtPages!C1:R1=Dashboard!G18)), dtPages!T:T,Dashboard!X11,dtPages!U:U,Dashboard!X13), "ERROR")

By using

SUMPRODUCT((dtPages!C2:R)*(dtPages!C1:R1=Dashboard!G18))

Instead of the INDEX formula above. But I get an "Argument must be a range" error.

Try either

=IF(AND(Dashboard!G11="All", Dashboard!G18<>"All"), SUMIFS(INDEX(dtPages!C:R,0,MATCH(Dashboard!G18,dtPages!C1:R1,0)), dtPages!T:T,Dashboard!X11,dtPages!U:U,Dashboard!X13), "SOMETHING")

OR

=IF(AND(Dashboard!G11="All", Dashboard!G18<>"All"), SUMIFS(INDEX(dtPages!C2:R,0,MATCH(Dashboard!G18,dtPages!C1:R1,0)), dtPages!T2:T,Dashboard!X11,dtPages!U2:U,Dashboard!X13), "SOMETHING")

Aligning C2:R, T2:T, U2:U within dtPages tab to have same row size to fix the Array arguments to SUMIFS are of different size error

Alternate formula to try out

=sum(ifna(filter(choosecols(dtPages!C2:R,xmatch(Dashboard!G18,dtPages!C1:R1)),dtPages!T2:T=Dashboard!X11,dtPages!U2:U=Dashboard!X13)))