Should I include all authors for in-text citation if I cite a source with three (or more) authors in a different chapter again?
Though not explicitly stated in the original post, the question pertains to the use of "et al."

This is mostly a nonissue for APA 7th edition because three or more authors are now cited as "et al." from the first mention, whether parenthetical or not, except where it would create ambiguity.