You can't set angles for the satin stitch, but you can when you use columns. If you already digitised satin stitch, use Convert, Create Column from Outline - no need to start anew.
Select your column, go to the edit mode and move your nodes - I used a guide line rotated 45 degrees to get the right angle.
Selecting sample 2 in parameters gives a better result than sample 1.
In theory you can use auto column (starting with a fill object), then put in direction nodes - but I am not very successful with that for larger areas.
Good luck.