How much money should I bring to settle in Japan ?

Hi, in few months from now I will be moving to Japan to work in a tech company. I make 7M JPY annualy, not including bonus. My company only covers my visa and airfare ticket, no temporary housing, moving in money or anything else.

Now my question, how much do I need to settle in Japan ? I know it will be near-impossible to secure long-term apartment from abroad. Therefore, I plan to move to short-term apartment (any ideas where to find it?) first which should be near my my office on Shibuya as I need to do onboarding stuff on first two or three weeks. After that I can work remotely and plan to secure long term apartment/detached house in Kanagawa or Saitama area.

I do not want to stay too long on short-term apartment (1-2 months is enough) as short-term furnished apartment expensive and I know I will need a lot of money to pay key money, deposit and all the stuff to move in to long-term apartment. Therefore do you guys have any idea how much money that could be considered safe if I want to secure long term-apartment in the third month, currently in my estimation I probably able to bring around 800k – 1.5 million JPY when I landed in Japan.

Another thing, for long-term I have a preference to secure a detached house, is it easy to rent a detached house for Gaijin in Kanagawa or Saitama area and is Suumo a good platform to rent a detached house ? Also how much is the price difference between Apato and Mansion ? I am asking because I plan to bring my kid and wife (probably after 6 months in Japan), and I have concern that my kid will bring much noise if decide to stay in Apato.

Thank you !

by Electrical-Sea9681