One of Witch Cult Translations' translators created a full translation of arc 4. As he states many times, his translations are not a perfect 1:1 translation, but rather a very detailed summary. He is only known by his email, email@example.com. His translations can be found here.
Arc IV Interludes
Following Arc 4 is a series of interludes known collectively as One Day II, which take place between Arc 4 and Arc 5 (One Day I was the series of interludes between Arc 2 and Arc 3, the stories there are linked on our Side Content document).