Hide or conceal the lamp cable on the ceiling

It has something… but the problem remains, even more dominant, with so much minimalism.

Nope. The problem is solved in the most elegant way by making the ceiling outlet part of the supporting structure. No one who doesn't know will guess that this solution was born out of necessity.

Anyway, it looks a hundred times better than a monkey swing or a cable duct.

And slotting the ceiling is always a tricky thing. It also affects the structural integrity. If you go too deep and hit the reinforcement... I wouldn't risk it.