I feel the same way about relics the whole ... I don't like having to rely on a wonky AI to come and beat some of my Apostles. I get what a relic is, but that mechanic seems entirely unreliable / silly.
I just finished cultural victory on deity with Kongo; I simply sent my apostles into rival religions' cities and put them to sleep there until the rival civ spawned apostles of their own. I would have gained a total of ~15-18 relics this way but didn't have room for more than 10 or so in the end.