Excel formula to count how many times the same 5 names show up with the same date. aka NBA lineup

Hendew44 Here's a couple more MS365 options to add to the mix...

Using a 2-dimensional COUNTIFS array (by player and date):

=SUM(BYCOL(COUNTIFS(C5:C500, E5:E9, B5:B500, TOROW(UNIQUE(B5:B500))), LAMBDA(c, PRODUCT(c))))

Or simplified with WRAPROWS (by player):

=SUM(BYROW(COUNTIF(E5:E9, WRAPROWS(C5:C500, 5)), LAMBDA(r, PRODUCT(r))))

Hendew44 

Try this one:

=LET(
    unique_dates, UNIQUE(Lineups[Date]),
    TotalStarters, LAMBDA(a, v,
        LET(
            game, FILTER(Lineups[Player], Lineups[Date] = v, 0),
            tally, IF(COUNT(XMATCH(starting, game)) = 5, 1, 0),
            SUM(a, tally)
        )
    ),
    REDUCE(0, unique_dates, TotalStarters)
)

Hendew44  This should work (but there may be easier ways):

=LET(roster_list, B2:D31, name_list, G2:G6,
sorted_starters, BYCOL(WRAPCOLS(TAKE(roster_list,,-1),5),LAMBDA(a, TEXTJOIN(",",,SORT(a)))),
sorted_name_list, TEXTJOIN(",",,SORT(name_list)),
SUM(--(sorted_name_list=sorted_starters)))

EDIT: for example this is slightly more concise:

=LET(roster_list, B2:D31, name_list, G2:G6,
starters, WRAPROWS(TAKE(roster_list,,-1),5),
SUM(--(MMULT(--ISNUMBER(XMATCH(starters,name_list)),{1;1;1;1;1})=5)))