why "chefen har kontroll alltid" wrong?
The adverb (alltid) usually comes after the verb (har) in main clauses.
There is no particule ?
Nope, no particle.
Why not 'alltid i kontroll'
Swedish simply doesn't have this expression.
Can we say here "koll" instead of "kontroll"?
No, that doesn't work. Are you thinking of the expression ha koll? In that case, it's more like keeping tabs on things.