The art style looks like Warehouse and the ML looks like Luka...ler's gooo

Alien stage?

Yep

in which way:' why can't I see Luka's wavy blonde hair at all

Well he has this sly deceptive vibe and he's probably a gaslighter and has a toxic personality which resembles Luka's.

but luka is physically sick. so it's only normal for him to act out of sanity.