I love the name
Selah! I agree that people may assume that it’s a girl’s name at first, I think it’d be fine to use for a son as well. Like someone else said, you could use it as a middle name to be safe.
Some other similar boy/gender neutral names:
SilasSaleh SolonSalem Sullivan /
SullyStellanSashaShilohSethCyrusCylis