You have a condo, so the 400v is because the building is being supplied with three-phase power - 63A gives you a total of 25KW which is certainly a lot, but nor

You have a condo, so the 400v is because the building is being supplied with three-phase power - 63A gives you a total of 25KW which is certainly a lot, but normal residential service is usually 240V @ 100A because of HVAC needs so it’s really more or less the same. RCD breakers really are a wonderful thing though, I had my second small fridge knocked out because I had accidentally hit the test button of the outlet near the kitchen sink that the dining room outlet was fed from - having it at the breaker makes it a whole lot less confusing and removes the searching for the protected outlet conundrum.