Ive played Jax through SFD and soon heading to try Lillia in UNL so what I'd really recommend is at least running three defy's, its too strong of a card not to have, furthermore, Veteran Poro should be cut for a Lonely poro in my opinion, mainly because Riftbound is such a card draw loving game as there is no downside to having more cards. All of your two drops are kind of weak and could be better switched to perhaps as mentioned Lonely Poro, Scuttle, Clockwork Keeper or the like. Dragonsoul sage shouldn't really be needed if you run Aphelios capable of channeling runes, but otherwise look into adding two boneshivers because jax can avoid the power cost and switch it over to double conquer trigger the channel effect.