Exchange semester in Japan 2027

Hi, im a 22 year old student from Portugal studying mechanical engineering and im curious on the japanese culture and wanted to do a semester abroad. My university offers me 4 choices: Doshisha University, Keio University, Osaka University and Ryokoku University.

Im here writing due to the fact that ive tried to find on my own but i wasnt able to find much info. Can anyone that has lived through this advise me? Im searching for a big city with alot of things to do and travel, want a rather laid back than hard university so i can enjoy my time of my country. Besides this, if anyone has an estimate on how much will the totality of expenses amount to.

Please, if you think that japanese universities are really hard and will make me go to every class, i would appreciate the heads up. Any info to distinguish these universities from themselves will help me due to the fact that i know close to nothing until now.