Yes, you sure are winning one of the martinking frustration awards. Every year or so we seem to have to have a couple of fishless cycles like this to remind us that we certainly don't know everything and there must be other major controlling factors out there that we'd love to know about and be able to test.
I sometimes draw solace when I'm trying to read some of the scientific journal output that is part of the waste water treatment plant world (yes, this is one of the few places from which we can try to draw tidbits of information, even though many of their things can't really apply as either their water chemistry situations or their equipment or their goals don't really match ours) as I find they have many of the same frustrations with the nitrifiers. Mother earth just doesn't seem to always give her magic with complete freeness!
We've had both sorts of endings to these super-frustrating cases, either they -finally- break as the cycler person "out-stubborned" them or they did indeed reach a point where their favorite stock was ready and available and they successfully switched over to watching them as if in a fish-in cycling situation.
~~waterdrop~~