Driveline noise/vibration

[Tanker93]

Id honestly just give it to a shop to balance. Seems too odd that the issue began straight after work was done on that component. You need to rule that out or you'll kick yourself later if that ends up being the issue.
Jack the drive axles up, put them on stands and run the truck up to see what happens, do this before and after the shaft is balanced.

You seem clued on enough but obviously practice with caution when doing so!