QGridLayout row positioning

[MAX001]

How can I place a row with buttons as high as possible at the top and take all the remaining space with a QWidget with a QGridLayout to display the opened image and the resulting image after defining the objects on it? So that the top row is always fixed at the top, regardless of the size of the window. I added setFixedHeight but the row is still not at the top and can I somehow avoid setFixedHeight for adaptability?

There was an idea to apply the stretch property but I don't know how to add it to each row and will it work as I wanted?
This is the result on the open window:

Wanna such result without top spacing

[MAX001]

Seems like done. Helped stretch property.
PS grid.setRowStretch(0, 0) 0 row stretch 0
grid.setRowStretch(1, 6) 1 row stretch 6