Makarov already managed to restrain Acnologia, Christina already managed to run him over. You don't need to be a dragon to hurt Acno, just physical strength is enough. You know this, but it undermines your arguments.
I feel like I'm repeating myself, but I'll do it one last time. Dragons possess magical resistance through their scales, so no Star Dress would be superior to the Taurus form in situations where Lucy needed to subdue a dragon with physical strength. Do you understand? The Taurus form is physically stronger than all other forms. It's not about Merc being a water dragon; he could be a fire dragon, and Aquarius magic would be useless because he has scales that give him resistance to common magic, which isn't dragon slayer magic.
Using Karameel is a very weak argument, considering all the disadvantages Lucy had in that confrontation, Hiro made sure to exemplify. He even had Brandish mention that Lucy was getting distracted during the confrontation.
The narrative already stated in the Viernes arc that Lucy and Brandish are on the same level, but if you're going to question that to further your agenda in favor of the Spriggans, you'll do it yourself because I don't intend to waste my time discussing what Mashima has already explained.
And this argument that Lucy is afraid of Brandish only works in your perception, since in that arc it was shown that Lucy intended to confront her for the Aquarius key.
The Spriggans' level has already been surpassed; the defeat of God Serena, the fifth strongest Spriggan, is a very illustrative example of this. The power level of the villain groups has begun to increase.
I'll stop here; I don't think we'll reach a consensus, even though the facts are well established in the narrative. I mentioned the fact that you ignore Lucy in all your posts praising feats that Brandish is unable to replicate on her own, as a way to refute your arguments, which overestimate the Spriggans to unrealistic levels.
None of them compare to a Dragon God.
And if I'm not mistaken, Mashima already made a power comparison between Ignia and the 12 Spriggans. I'll look it up later.