create custom formula

pevenden If you have Excel for MS365, you can achieve the same results as the graph you've shared with the following formula:

=LET(n, B1, k, B2,
φ, IF(ISBLANK(k), 1, k),
MAKEARRAY(n, n, LAMBDA(p,a,
   IF(p>a, "", IFERROR((p*(1-((50*a+4800)/98))+((a*(50*a+4800))/98)-1)/(a-1), 25)*φ))))

...where the attendance (A) is in cell B1 and the fleet factor (φ) is in cell B2. The results would look something like this:

MAKEARRAY Chart with Conditional Formatting

Conditional Formatting was applied to range C5:V24 to shade the empty string results blue using the following formula:

=AND(NOT(ISBLANK(C5)), C5="")

You could also create a custom LAMBDA function in Name Manager to award points to each team based on their finishing position for each race. For example, you could create a function called XPOINTS using the following formula:

=LAMBDA(a,p,[φ],
   LET(
      k, IF(ISBLANK(φ), 1, φ),
      IFERROR((p*(1-((50*a+4800)/98))+((a*(50*a+4800))/98)-1)/(a-1), 25)*k
   )
)

...then use it as follows:

Custom LAMBDA Function

The formula used in cell D4 in the screenshot above is:

=XPOINTS(COUNTIF($A$4:$A$20, A4), B4, $B$1)

...where COUNTIF is used to calculate the total attendance (A) for each Race No.

As for the Season Standings section shown above, the following formula was used in cell F4:

=LET(
u, UNIQUE(C4:C20),
a, SORT(HSTACK(u, SUMIFS(D4:D20, C4:C20, u)), 2, -1),
HSTACK(SEQUENCE(ROWS(u)), a))

I've also attached the workbook for your convenience. Cheers!

pevenden as per the new information provided by JoeUser2004 regarding "the system includes your best five regatta finishes", the formula to generate Season Standings in my above response can be modified to sum the results of each team's best 5 finishes as follows:

=LET(
u, UNIQUE(C4:C20),
a, BYROW(u, LAMBDA(r, SUM(TAKE(SORT(FILTER(D4:D20, C4:C20=r)), -5)))),
HSTACK(SEQUENCE(ROWS(u)), SORT(HSTACK(u, a), 2, -1)))

Please see the attached updated workbook (v2).