You can change the (inner) position of the stacked plot - https://in.mathworks.com/help/matlab/ref/matlab.graphics.chart.stackedlinechart-properties.html#mw_9c083e4b-17d1-41fa-85ff-99906ce25d7d
The values in the Position property correspond to [left bottom width height] and the default unit is normalized, w.r.t the whole figure i.e. lower left corner maps to (0,0) and top right corner maps to (1,1)
tbl = readtimetable("outages.csv","TextType","string");
tbl = sortrows(tbl);
figure
h1=stackedplot(tbl);
%Default position values
h1.Position
figure
h2 = stackedplot(tbl);
AR = 1.5;
width = 0.6;
%Modified values
h2.Position = [0.2 0.1 width AR*width];