I think this is definitely more than what my small kitchen requires.
My concern with running 2x cables  is what if there's a discontinuity or uneven load carrying capability in one of the cables - loose connection, cable fault/breakage, etc? Before the MCB trips, the wire that supports more load may overheat.
That's what I think too. But costs almost double that of 4mm² .  Rather having just one set of wires (either 4mm or 6mm) than the messy 2x2.5mm² system (6 wires to pull).
Internet research gives varying load of 4mm² wires, on paper it's sufficient for the present needs. So I wonder if it's too kiasu to go for 6mm².