Here the original manuscript reads “these things matter not”. When Oliver Cowdery copied the text from 𝓞 into 𝓟, he replaced matter with mattereth. In the original text, there are many instances where plural nouns took verbs ending in the historically present-tense singular ending -(e)th. For this possibility, see the discussion regarding the expression “Nephi’s brethren rebelleth against him” in the 1 Nephi preface (discussed in part 1 of volume 4). Here in Alma 54:22, however, the original text has the standard null ending for the verb matter. Interestingly, the 1920 LDS edition restored the original matter, not by reference to 𝓞 but in accord with the standard rules of subject-verb agreement. For further discussion of the phrase “mattereth not”, see under Mosiah 13:9.
Summary: Maintain in Alma 54:22 the verb form matter (“these things matter not”), the reading of the original manuscript.