Background photo is from Rags (or Lags?) in Nakano, an apartment complex where Uika canonically lives. This means it's likely that her home was modeled after the exact one shown here.

https://maps.app.goo.gl/LSaHb7UGSjT4E91z9

35° 40′ 58″ N, 139° 39′ 40″ E