Two Ends of the Same Spectrum

We can all generally and confidently agree that there is a similarity between Metamorphosis and Notes from Underground in that both deal with a character that lacks any real purpose due to a social estrangement that goes hand in hand with the "ennui" both authors seem to address in their works. Both Gregor and UM occupy that same state of spiritual paralysis or emotional detachment, but they do so in conflicting ways. UM comes off as a if not selfish, a self-absorbed person due to his ego and insecurity, but Gregor is probably one of the most selfless individuals I've encountered in literature. Nevertheless, they cannot grasp any real purpose in life as they are the sources of their own deterioration. UM can't do so, because he's unable to go beyond himself or his thoughts, and Gregor's purpose other serving others is hollow in that he sacrifices the enormity of his entire life to satisfy the petty comforts of others, in other words he'd willingly die to make someone else happy.