I get it why people complained about the friend.
Essentially isekai mangas are wish fulfillments but MC's has a cheating wife (it's obvious) so he is being cucked and doesn't adress it or even shows a slight interest. His skills are quite bad.
On the other hand we have his friend with super skill from the get go, who is super competent, loved by the people, praised by the employer and banged a girl from the start.
While MC is being cuked, somewhat looked down upon by others (not much but it feels that way).
If it was balanced? I see no problem but author created unfair scales. I would even think that author imagines himself as that friend.......So yeah feels like author is trying to overshadow MC with his wet dream.