Primaris combat performance?

So Primaris are marketed as the upgrade to the Firstborn marines.

Is there lorebooks and novels where the enemies of man is reacting to Primaris and they are changing tactics, and adapting to account to the improve performance and new toys of the Primaris

I wanted to know if there has been a mark of improvement because I feel the Primaris still die in droves like their firstborn cousins and the xenos and chaos can still kill them fine like regular marines.