I loved the Quilt in a Day FG rulers, until I tried the die cutter. The die cut ones go so fast and easy, I won’t go back to rulers.

Google no waste flying geese, there is a method that starts w/ squares and makes 4 flying geese at a time and I find it the easiest way especially if all the flying geese (or at least 4 of them) need to be the same fabric.

I found it here is a link

https://weallsew.com/no-waste-flying-geese/

This is the way I do them

Did you check your seam allowance? It looks like you are doing a very scant 1/4 inch. That may be your issue.

Agree with Kassaundra on the no waste method. Also like the stitch and flip and trim. When you use only the triangles, the issue is with the bias.