Here Oliver Cowdery produced a virtually immediate correction in 𝓟 by adding the plural s to his initially written suffering (there is no change in the level of ink flow for the inserted s). In theory, either singular or plural will work here, although the Book of Mormon text has only instances of the plural sufferings when referring to Christ’s suffering and death (see the discussion under Alma 16:19). The critical text will maintain the plural sufferings here in Alma 22:14.
Summary: Retain in Alma 22:14 the plural sufferings, the corrected reading in 𝓟; the text consistently uses the plural sufferings when referring to Christ’s atonement.