What is the best way to organize the user input of a matrix?

Question

User interface

Hello.
On the page I want to receive data from the user to fill in the matrix:

The size of the matrix is ​​set by the user and the final page layout depends on it. On the one hand, I don’t want to severely restrict the user in choosing the size of the matrix, on the other hand, already with 16 or more rows, the table will need to be “scrolled”, and with 25 or more elements, the table begins to expand beyond the page. I wanted to ask for advice, what would you do in this case? What if, for example, you need to enter a 100x100 matrix?

Answer 1

Is it just an input, or will the values ​​in the matrix then be changed by the program?
In general, a good example is Excel.

Answer 2

Well, what to do? Google tables work on the same principle, you still have to scroll when there are a lot of rows or columns