Only the ascender of the l in evil is extant in 𝓞, but since this ascender could also belong to a d, we have to consider the possibility that 𝓞 actually read wicked. The small lacuna in 𝓞, however, argues against the longer wicked. And although Oliver Cowdery initially wrote wicked in 𝓟, he virtually immediately corrected it to evil (the level of ink flow for the supralinear evil and for the crossout of wicked are unchanged). Here the 1830 edition, proofed against 𝓞, reads evil. The critical text will therefore accept the corrected reading in 𝓟, “the evil one”, as the original reading as well as the reading in 𝓞.
Elsewhere the text has six examples of “the evil one” but none of “the wicked one”. On the other hand, the King James Bible has only “the wicked one” (four times). Here in Alma 46:8, Oliver Cowdery initially wrote “the wicked one” in 𝓟 probably because the following text has two instances of the morpheme wicked: “yea and we also see the great wickedness one very wicked man can cause to take place among the children of men” (Alma 46:9). The critical text will therefore accept the corrected reading in 𝓟, “the evil one”, as the reading of the original text as well as the reading in 𝓞.
Summary: Maintain in Alma 46:8 the corrected reading in 𝓟, “the evil one”.