If you ask why Kanami insists on bringing Maria, the reason is simple. He just can't stand being alone. But rather than ask for help, he would make the other party want to join him instead. You can see how depressed he was before he met Dia and Maria. But somehow he can become the most reliable person in front of them. The manga doesn't explain that he is a former child actor.
That's why it's really fun to see his acting seeing through. It's like the reverse of a trope where the MC does something easy but everyone praises it so much. Kanami tries very hard to keep his image but some characters like Maria and Palinchron can see it and they are surprised by how normal he is.