Reviewing your bowling against the coaching manual, you can see in the video the following two issues:
1. Your general alignment into delivery then follow through. your back leg is out to the left hand side while your front leg is roughly 12 inches across the crease to the right. You can see that in this part of the video:

My comment about you throwing your leading arm out to the right maybe linked to this, but your alignment is somewhat off kilter.
2. You deliver from a massively laterally flexed position:
1st Ball:

2nd Ball:

With alignment showing:

Look where your head is in both these deliveries. Your whole body is bent over to the side, so maintaining control and generating pace is going to be extremely difficult.
In both cases your body is managing your balance rather than fluidly maintaining your pace through the delivery. Your lateral flexion will also mean that the arc your arm will draw is as below:

With your body moving as it is and the way your arm is following, you are essentially generating outswing through your action and not through the tools that Dale Steyn uses. If you can get yourself upright and aligned, those may be much more use.