Deadfire DLC's (at least 2 of them) are not properly balanced, no question about that. The natural power curve in the main game is broken with the DLC's, causing the issue of a huge spike compared to regular MQ. Not really defensible other than allowing for the hardcore uber gamers to get their fix, but it should be advertised and scoped like that instead of awkwardly shoehorning it into the game when players expect the same level of hardship on the same difficulty and not a spike just because its DLC content. It's been really killing my enjoyment going from being able to confidently handle regular end-game encounters to being destroyed by the HP sponge enemies. The only DLC that was fair in my opinion was the Rymrgand one, the others are a cheese factory.
As for Boeroer's suggestion that "most players have no issues with increased difficulty of DLC's" I'll assume this is coming from the ether of made-up-statements unless you have some actual backing. I'd wager it's more likely that most people just avoid the DLC's when finding the difficulty spikes, or resort to cheesing using full custom party, or lower the difficulty. One shouldn't have to alter their entire playstyle in the end-game for DLC's.