Well, it was half dead. So it takes time. That said, you should have really good azalea weather. Not sure why it stalled.
I would say, partial shade, high night temperatures, humidity, good soil, moderate organic fertilizer (or liquid in substrate/100% kanuma) should do the trick.
Low night temps, direct sunlight, bad roots, they could all inhibit growth. A struggling plant won't grow much.
I do see long new shoots on your last picture. What exactly is the status and issue now?
Still trying to figure this out myself, though.