The instances noted show the criteria by which to worry. If you bomb the house of Neil Armstrong the night before the moon shot, history remains unaltered. If you blow off Armstrong's head with a shotgun the night before the moon shot, a few names in history may get altered but that's all. If you nuke Apollo 11 in midflight and make it look like the Soviets did it, then the general course of history might change enough for somebody a couple of centuries distant to notice.
Whether the E-C had crew aboard, or just crash test dummies, doesn't sound like something that would have any effect. Or if it did, our heroes should remain convinced that they themselves and everybody they ever heard of would stay unaltered, because that's what always happens with Trek time travel.
Timo Saloniemi
Except that the butterfly effect is alive and well in Star Trek. For you to claim it is categorically not in there requires that there not be a single instance anywhere in the entire canon. One supported instance and things fall apart.
Edith Keeler survives, a result of McCoy jumping to save her, the Federation does not come into being. Regardless of any other changes which did or did not occur due to the heroes actions in the show (and it is far from established that they had no effect, merely that we notice none in our very small onscreen snapshot of the ST universe), that fits the definition.
Cause and Effect, Data sends messages to himself through a temporal loop (a tiny change), using his positronic circuits, as a result the timeline is altered, both the Ent and the Bozeman survive (bigger effect, though predicted), the crew are still about for AGT to prevent the entire galaxy being devoured by a subspace (vast and remote effect, completely unpredicted). The original (sans rift) timeline is not restored - the Bozeman herself continues to serve in the 24th century SF with unknown ongoing effects on the timeline
Year of Hell, basically an entire double episode devoted to the butterfly effect (and commonly used as an instance in the popular culture to explain the concept), every change Annorax tries, no matter how obscure, results in vast sweeping and unforeseen changes to the timeline - he just cannot get the outcome he wants.
Yesterday's Enterprise itself, the fact of the C flying into the temporal rift could boil down to tiny movements of the helm officers fingers, (avoiding it, whether intentional or not, would have simply been a case of entering a different course during the heat of battle) which led to the completely unexpected result of the federation facing destruction at the hand of the Klingons. Again, even after the "resolution" we have no definite answer as to whether the timeline is truly restored, all we know is the tiny bit of it we see seems pretty close.
Frankly the number of possible instances of butterfly effect are littered throughout the franchise, these are just a tiny choice of possibilities. Many you will doubtless refute on the grounds that restoring the timeline technically discounts them (assuming in each case we can be confident that this has in fact happened) but there is at least one clear cut instance (Year of Hell) and several that sit pretty close and require some creative thinking to give a definitive answer either way.
In either case, as your argument rests on the premise that there are NO such instances, just the one is enough.