Enigma- I hear your frustration! I have two MP's and neither suffers the cable angle you show in your photos. Also, neither of my MP's have that knocking sound during start-up. It's not normal.
However, a week ago I was testing a bottom 360VR camera mount and the experiment failed and caused the MP to crash into the grass from 98ft. The only damage was the gimbal ribbon cable, making it dead as a door nail. I decided to do the repair myself as I have a bit of experience doing electronic repairs, but never anything this difficult. Anyway the repair did go well and I'm back in business.
Here's what you need to know- There are a number of companies that sell replacement cables. I chose one based on delivery. They all range in cost from $12 -$20, some with free shipping. I selected one that cost $15 free shipping. The size of the original cable and my replacement is different in quality of materials with the original looking less durable. Mine broke clean off from the crash right where it leaved the gimbal mount and runs to the circuit board. The new cable is actually a bit wider than the original too. But, overall length from connection to connection of each motor is the same.
After the crash I noticed the gimbal was not hanging plumb but after removing it the shock plate was bent so I had to straighten it so the assembly didn't hit anything when I started up. I'm wondering if your gimbal plate or the rubber shock mounts are not installed properly causing the knocking sound. For some reason, many fliers have had the shock plate get bent or cracked and I was no different.