You've heard about shift left. Finding and removing bugs earlier, closer to the point of introduction, makes sense, because it's cheaper to remove bugs earlier and it increases developer productivity by reducing debugging work. However, you should also be looking to shift down, too. Shifting down means introducing fewer bugs to begin with, and, of course, the cheapest bug is the one you don't have to pay to fix because it never existed.
If you're looking to shift left and shift down, but can't quite figure out how to do that, contact us. We've been helping clients shift left and shift down since 1997, so we have over 20 years of experience.