Osaka self-help tour, four and a half days. Is it necessary to buy JR Pass? Where is more convenient to live?

Don't buy Jrpass if you don't have multiple round trips to intercity. For example, you can buy Icoca directly and brush the value directly. For example, the price of 7-day jrpass is equivalent to the round-trip ticket price from Osaka to Tokyo, which means that if you go to Tokyo from Osaka one way and then fly back to China from Tokyo, there is no need to buy jrpass. Therefore, if you only play in Osaka or go to places near Osaka such as Kyoto and Nara, you can buy tickets separately without buying jrpass. As for where to live, it depends on which scenic spot you want to go.