Out of curiosity, have you tried to shoot the gun without a magazine? If yes, what happened?
If it was stovepiping, the usual culprit is the extractor losing control of the rim while it is being pushed up by the magazine or the round is not having enough oomph to push the round into the ejector with enough force to send it flying (too much recoil spring). Honestly, I have never found the shake test to be a great help other than perhaps getting to a starting point to adjust from. A test I use, i(f you don't trust yourself, pull out the firing pin for this) load a magazine and as fast and violently as you can, yank the slide back and let it go while having a firm grip on the gun. You aren't going to match the slide velocity but it is very helpful in seeing things. If it can go through a box of ammo, I move on to shooting without a magazine. If it can shoot without a magazine and it extracts properly, I know I have it set pretty good.
Just another thought, this is a 9mm, how does your ejector look. The longer ejectors can break.
I am not a gunsmith but I love to build 1911s. I have ground up built 6 so far plus done a bunch of work on others. I am not an expert, just someone that messes around.
Edit: that brass looks pretty rough, is your chamber smooth?