The term “amen” is a very biblical word and concept used inclusively in the Bible. The fact that it is similar in spelling and sound to the name of a long-forgotten Egyptian sun god (at least for all practical purposes) is of no consequence unless one were using it in some kind of cult for the worship of this ancient false god who was no god at all.
As Christians use the term “amen,” it is not used as a name, but as an expression of agreement, a strong affirmation of a truth, or at the close of a prayer. It is the use of words in a particular context that give words significance and meaning and not merely the sound. The sound of a word is sometimes significant as a play on words, but again, it is the usage in the context that counts. An illustration of such contextual word plays can be seen in Genesis 18. Here the sin of the city is so great that it virtually cries out to heaven for retribution (verse 20). But there is a play on word sounds here between the “outcry” and the Hebrew word for “righteousness” which is part of the theme of this passage. Se’aqa, “outcry,” versus sedaqa, “righteousness.” The point is, God’s judgment against Sodom comes against the outcry of sin because of His holy righteousness.