I understand him pretending to be weak and naive is apart of the comedy aspect but it does bother me. I wish he could be his true self in Japan
as SoupEnergy mentioned, his entire character is based on acting like a weak mob
even before he reincarnated, so he is still his 'true self' since he never changed.
Also, he actually died in japan, and literally knows nothing about the major changes in the last 3 years, pretending to a weak amnesiac is so akane and other people wouldn't think he is too suspicious.
I also hate he left Beta by herself.
Him continuing his chuuni act aside, he really doesn't need to babysit her since she
is strong enough to protect herself, and he does want to leave japan and return to his world, so extra mishaps in Japan probably wouldn't really matter anyways.