Lukaku doesn't have the game that fits Arteta's set up. Why you think he pushed Auba wide and kept playing LacaThreat even tho he couldn't score in a brothel with no management or security.
And while he is a better scorer than Nketiah. Nketiah has a better mentally that suits Arteta than Lukaku who we moaned about the French clique at United and shows negative body language when things don't go his way.
Maybe I'm still too old school in my thinking but I think they would benefit from having a different profile player in the team. But it seems like these days managers have a set style of playing and everything else is a non-starter.
As far as mentality you're 100% right he will eventually end up sulking no matter where he goes. But I'm thinking going from Chelsea to Arsenal would light a fire under his ass at least for a season. Kind of like Adebayor in his first season at Spurs after doing nothing at City and Madrid.
I really don't understand paying that money for Kai Havertz, it makes even less sense than United paying 65m for Mount.