iserith
Magic Wordsmith
Just being trained in religion is probably sufficient for a lot of the knowledge checks. The cases where it isn’t sufficient, should be weightier or more significant scenarios than “Who’s that poke-undead?” IMO, anyway.
Right, as with the mention of background above, informing the DM that your character is drawing on, say, formal religious training at the monastery before it was burned down by pillaging orcs from across the sea, is both helping your DM fairly and consistently adjudicate the action while entertaining the table with an interesting tidbit from your character's past.