The word "most alternately" can be substituted with various synonyms, depending on the context of the sentence. If the sentence is meant to convey the idea of "most interchangeably," some synonyms include "alternatively," "in turn," or "by turns." If the sentence is intended to convey the meaning of "most frequently," synonyms such as "often," "repeatedly," or "regularly" can be used. Additionally, if the sentence is meant to convey the idea of "most diversely," synonyms such as "variously," "differently," or "multifariously" can be used. It is important to carefully consider the context of the sentence before selecting a synonym.