>>47215264I just did. Shedinja.
Shedinja gains no HP from Dynamax, and the dynamax moves are of universally inferior quality to its own basic moves, as it looses out on Shadow Sneak's recovery, Wil-O-Wisp spreading burns to switch-ins, setting up with SD, and more.
Shedinja not only does not get better when Dynamaxed, it actually gets worse, because it can no longer use its abilities to pivot and harass the enemy, which are integral to using shedinja.
Even the power boost is irrelevant to Shedinja, as the only move Shedinja actually cares about powering up is Shadow Sneak, to take out more targets first, which again, Dynamax actually prevents Shedinja from doing.
Lesser case for Aegislash, which can no longer change stance while Dynamaxed, again, actually nerfing it overall, since it either deals piss damage if Dynamaxed in Shield form, or can't take a hit if Dynamaxed in Sword form. Unlike Shedinja, there could theoretically be a situation where Sword form Aegislash may appreciate the power boost to finish of an enemy, but this would be an incredibly rare situation, since the loss of its ability makes Aegislash drop to a piece of shit the moment it isn't in the right form.
Now, these comparisons are ultimately asinine, because you seem to be unable to comprehend the idea of an opportunity cost, but fuck it, I'm not going to try and teach you that now.
Here you are, not just one, but TWO pokemon that objectively do not benefit from Dynamax, and are in fact harmed by using it.