Slice the Scotch Fillet steak into thin strips, approximately 1/4 inch thick. For easier slicing, partially freeze the meat for 20-30 minutes before cutting.

In a non-reactive container, such as a glass bowl, combine the soy sauce, sweet chili sauce, onion powder, and garlic powder. Mix thoroughly to ensure all the seasonings are well incorporated.

Place the sliced steak into the marinade, ensuring all pieces are fully submerged. Cover the container and refrigerate for a minimum of 4 hours, or preferably overnight, to allow the flavors to infuse.

Remove the beef strips from the marinade and pat them dry using paper towels to remove excess liquid. Arrange the strips on the dehydrator trays, ensuring there is sufficient space between each piece for proper airflow. Sprinkle red pepper flakes over the strips if a spicier flavor is desired.

Set the dehydrator to 70°C (160°F) and allow the beef to dehydrate for 8 to 14 hours, depending on your preferred texture. Begin checking the jerky at the 8-hour mark; it should be firm but slightly pliable when bent.

Once the jerky has reached the desired texture, remove it from the dehydrator and allow it to cool completely. Store in an airtight container or jar at room temperature for up to two weeks.