Broken syntax in formula

James_Pipe 

Here at least there is no syntax error

=IFERROR(
   IFS(
      [@Code]="SM", 1.5,
      AND( SUM( IF(
               IFERROR( LEFT([Name], SEARCH(" ",[Name] )-1 ),0 ) =
               ( LEFT([@Name], SEARCH(" ",[@Name], 1 )-1 ) ),
               1,
               0)
            ) = 1,
            XLOOKUP(
               LEFT([Name],SEARCH(" ",[Name])-1),0,
               Sunday2[Name],
               TRUE,
               0
            )
      ),
         IFS( AND(
            4<=($D9-$C9),
            ($D9-$C9) < 6,
            XLOOKUP( [@Name], AmendedHours[Names], AmendedHours[Break], 0) < Rules!$V$5
            ),
            Rules!$V$5,
            AND(
               6<=($D9-$C9),
               ($D9-$C9)<8,
               XLOOKUP([@Name],AmendedHours[Names],AmendedHours[Break],0) <Rules!$V$6
            ),
            Rules!$V$6,
            AND(
               8<=($D9-$C9),
               ($D9-$C9)<9,
               XLOOKUP([@Name],AmendedHours[Names],AmendedHours[Break],0)<Rules!$V$7
            ),
            Rules!$V$7,
            9<=($D9-$C9), Rules!$V$8,
            ($D9-$C9)<4,0
         ),
      AND(
         SUM( IF(
               IFERROR(LEFT([Name],SEARCH(" ",[Name])-1),0)=
               (LEFT([@Name], SEARCH(" ",[@Name],1)-1)),
               1,
               0)
         ) > 1,
         (RIGHT(
               XLOOKUP([@Name],Sunday2[Name],Sunday2[Name],0),
               LEN([@Name])-SEARCH(" ",[@Name],1))
         ) > "0"
      ),
      IFS(
         AND(
            4<=($D9-$C9),
            ($D9-$C9)<6,
            XLOOKUP([@Name],AmendedHours[Names],AmendedHours[Break],0) < Rules!$V$5
          ),
          Rules!$V$5,
         AND(
            6<=($D9-$C9),
            ($D9-$C9)<8,
            XLOOKUP([@Name],AmendedHours[Names],AmendedHours[Break],0) < Rules!$V$6
         ),
         Rules!$V$6,
         AND(
            8<=($D9-$C9),
            ($D9-$C9)<9,
            XLOOKUP([@Name],AmendedHours[Names],AmendedHours[Break],0)<Rules!$V$7
         ),
         Rules!$V$7,
         9<=($D9-$C9), Rules!$V$8,
         ($D9-$C9) <4, 0
      ),
      AND(
         4<=($D9-$C9),
         ($D9-$C9)<6,
         XLOOKUP([@Name],AmendedHours[Names],AmendedHours[Break],0)<Rules!$V$5
      ),
      Rules!$V$5,
      AND(
         6<=($D9-$C9),
         ($D9-$C9)<8,
         XLOOKUP([@Name],AmendedHours[Names],AmendedHours[Break],0)<Rules!$V$6
      ),
      Rules!$V$6,
      AND(
         8<=($D9-$C9),
         ($D9-$C9)<9,
         XLOOKUP([@Name],AmendedHours[Names],AmendedHours[Break],0)<Rules!$V$7
      ),
      Rules!$V$7,
      9<=($D9-$C9), Rules!$V$8,
      ($D9-$C9)<4, 0
   ),
0 )

It's hard to understand entire logic.