First of all, I think anything can be relevant to Christians.
Secondly, Hades in the Scriptures just refers to “the place of the dead” which was another understanding they had for the word among the Greeks, whose language was used to write the New Testament.
It implies no endorsement of or connection to Greek mythology.
It’s like if we use the words Sunday, Monday, Tuesday … if you look it up, these words are based on Roman mythology. Because we use and understand them does not imply that we endorse or connect ourselves to Roman gods.