Aren't the timing attacks you're talking about specific to oddball parameters for the handshake? If you're doing Dragonfly with Brainpool curves you're specifically not doing what NSA wants you to do. Brainpool curves are literally a rejection of NIST's curves.
If you haven't read the Enigma paper, you should do so before confidently stating that nobody's done "sanity checks" on the P-curves. Its authors are approximately as authoritative on the subject as Aaronson is on his. I am specifically not talking about the question of NSA's recommendation on ECC vs. PQ; I'm talking about the integrity of the P-curve selection, in particular. You need to read the paper to see the argument I'm making; it's not in the abstract.
Ah now I see what the question was as it seemed like a non sequitur. I misunderstood the comment by foxboron to be concerns about any backdoors not that P256 is backdoored, I hold no such view of that, surely bitcoin should be good evidence.
Instead I was stating that weaknesses in cryptography have been historically put there with some NSA involvement at times.
For DB: The brain pool curves do have a worse leak, but as stated in the dragon blood paper “we believe that these sidechannels are inherent to Dragonfly”. The first attack submission did hit P-256 setups before the minimal iteration count was increased and afterward was more applicable to same-system cache/ micro architectural bugs. These attacks were more generally correctly mitigated when H2C deterministic algorithms rolled out. There’s many bad choices that were selected of course to make the PAKE more exploitable, putting the client MAC in the pre commits, having that downgrade, including brain pool curves. but to my point on committees— cryptographers warned strongly when standardizing that this could be an attack and no course correction was taken.