Horrible formula in cell L3, copied across:

=LAMBDA(vals,groups,group,LET(b,MAX(BYROW(--(TRANSPOSE(vals)=FILTER(vals,groups=group)),LAMBDA(a,SUM(a)))),IFERROR(IF(b>1,b,0),0)))($I$2:$I$13,$G$2:$G$13,L$1)

all because COUNTIF(S) won't work with arrays.

Nicer formula in cell L4:

=MaxEqualValuesCount($I$2:$I$13,$G$2:$G$13,L$1)

which is the same formula, but used in a Name. You get a hint of what goes where:

2023-02-07_223319.jpg

and I've assumed if, for example, there are 5 values made up of 2 unique values, 3 of 1 and 2 of the other, you'll want the maximum only (3).

It would be good if someone could come up with a more elegant solution.