Go to the BP_SmartAIComponent and create a new variable called Projectile Speed and set the variable type to float and set the default value to 3000 and tick on Instance Editable.

Go to the location shown in the image below, location at the top of the screenshot.

Next make the changes shown in the image below.

Go to the location shown in the image below, location at the top of the screenshot.

Next make the changes shown in the image below.

Add the highlighted nodes shown in the images below, location at the top of the screenshots.