After solving the problem of charging my gadgets, there is only one problem: charging my Apple Watch. Since there is no Apple Watch charger at Big-C, I can only get it the next day.
I wanted to get the Apple Watch Magnetic Fast Charger to USB-C Cable (1 m) from Apple Store in Central World which is directly opposite my hotel, Moxy Bangkok Ratchaprasong. But it is way more expensive in Thailand than in Singapore. The official retail price of that cable is TH฿1,290 (S$52), and in Singapore, it is only S$39. So, I aborted the idea.