How can I find full apartments for 1 to 3 months rent ?

I currently live in Japan, I'm new here and I'm still deciding where to live permanently (Tokyo, Osaka, Kyoto) right now I'm staying in hotels which is kinda expensive. I want to spend 1.5 months in Tokyo, 1.5 months in Osaka and 1.5 months in Kyoto, but I don't want to rent Airbnb because I see they are overpriced and small/thin walls, and I do meetings everyday for work so I don't want to bother the neighbors, a house/good quality apartment would be nice but I don't know how to find a single month apartment rent in Japan, budget is not an issue but as cheap as I can go while maintaining good quality would be perfect.

Thanks for the help!

by No_Attitude8405