My car sounded absolutely bad&horrible each time an injector gave up.
I thought it won`t make it another mile.
Forgive my question, but it all sounds unclear to me, did you actually replace the old nozzles with new(-er) nozzles and then also bench-tested them (the injectors)?
Good and well-set injectors (properly set to factory specifications) make a ton of a difference in how the engine runs. You didnt share details on how and what you did on around the injectors but I assume you did change the injector heat shields also (to new ones). They absolutely must be replaced every single time you take out an injector.
I`ll try to find my video to share.
The timing might be off a little. The more you write on your repair, the more someone will be able to help you figure it out. The secret is in the details.
Also, a few VW Camper with d24 engine pictures would motivate the heck out of us.