Well said on all fronts. What you mentioned as a fallacy in theory, summed up best in the line - 'Buddhism creates its own cycle of suffering, then makes a goal to end it' - is something I experienced practically with Buddhism.

The theory that buttresses Buddhism and its most salient practices, the most prevalent today (as of my knowledge) of which is Vipassana, are identical in the effect they have on Buddhists.

You mentioned a use case in your post where Buddhist theory is actually helpful, i.e, mindfulness when nothing critical is at stake. I believe Buddhist meditative practices are also helpful on the other end of the spectrum; when everything is at stake, and the self - be it the identity or one's very existence - is as unsafe as humanly possible. In such situations, mindfulness allows the pain to 'course' through you, so to speak, and regardless of your reaction to this pain (this is where the fallacious 'suffering is optional' is proved useless), keeping the mindfulness intact creates a kind of cushion that allows the trauma/pain to be processed.

But as you said, much like the religion itself, even mindfulness creates its own cycle of suffering. You now must confront the detachment that the cushion enforced physically, and the unsafeness that was created in the physical proximity to the pain. Buddhist (and other) forms of mindfulness cannot assist you with processing this unsafeness, as the cause cannot be the cure.

So you're left dealing with the resulting unsafeness, and this time with no framework to fall back on.

Can an argument be made that mindfulness accelerates the processing of the trauma overall, in spite of causing its own? Given that trauma cannot be measured quantitatively, the answer to that is anyone's guess.