Christianity is very obviously, except to many of its followers, polytheistic. Moslems even object to christianity largely because of that.
Many Christians I've argued this with say, "well, Satan ans archangels and angels ane seraphim and cherubim and demons are all
created beings, so they can't be gods, so there!!" That's a pretty thin argument, it seems, and these same folks will also tell you the Son and Holy Ghost have always been around - "uncreate," as one of those Creeds says.