Issue:
IFS syntax is:
IFS(condition1,value1,condition2,value2,...)
It's important to realize all arguments should be of the same size. Same rows and columns. If there's a mismatch, this error is thrown
Expected row count: 1. column count: 1. Actual row count: 2, column count: 2.
What this says is, 1x1 array is expected, but instead the function got 2x2 array and it doesn't know what to do with that.
In this specific case, GOOGLEFINANCE returns a 2x2 array with it's headers, while WEEKDAY returns a 1x1 array.
Solution:
Either increase the 1x1 array to 2x2 array or reduce the 2x2 array to 1x1 array. Increasing can be done with array operations like ARRAYFORMULA(IF()) or IF(SEQUENCE()). Decreasing can be done with INDEX/QUERY or FILTER
Snippet:
=ifs(weekday($C$1-1,2)=6,INDEX(GOOGLEFINANCE($S$1,"high",today()-(today()-$C$1+4)),2,2),weekday($C$1-1,2)=7,INDEX(GOOGLEFINANCE($S$1,"high",today()-(today()-$C$1+4)),2,2))
GOOGLEFINANCE()function returning 2 rows. Share a sample worksheet.