Scribe 2 of 𝓟 initially wrote “there was continual peace in all the land”, but then immediately corrected his error by erasure and writing “that time”. There are 24 occurrences of “peace in (all) the land” in the Book of Mormon, including a nearby one in Alma 3:24: “and then they returned again and began to establish peace in the land”. The unexpected “peace in all that time” was undoubtedly the reading in 𝓞; there would have been no motivation for scribe 2 to have edited the text here. The critical text will therefore maintain the corrected reading in 𝓟: “and there was continual peace in all that time”.
There is only one other instance in the text where “peace in” is immediately followed by a reference to time:
Summary: Maintain in Alma 4:5 the corrected reading in 𝓟, “in all that time”.