Turbocharger?

[Ravenwood]

I now have a new issue with my CM2350 and I’m thinking it might be the vanes are hanging up. If you’re familiar with my past issues a lot of coolant was pushed through this turbo this spring.
Whenever my engine brake engages whether manually or on cruise. The VGT tries to do something but extremely weak. If I cycle the switch down to 1 and back to 3 then it will work. If I give it fuel to downshift it will stay but any power whatsoever and I have to cycle the switch again.

Also if I’m on a really hard pull with a step in it that brings my rpm’s up to about 1900 until the next step up. The engine will start to shake, black smoke, no power (feels like it’s going to fuel knock) until I let off completely and let the engine brake bring my rpm’s down to idle and quickly grab whatever gear I can before I stop moving. (this only seems to happen if I let my rpm’s climb up passed 1700)
I did the actuator tests and it passes. No codes on Insite.

Any advice, answers or suggestions would be greatly appreciated
Thanks in advance.