I'm not sure how well the game incentives prestige by making the Voids hard to beat. I haven't prestiged yet, am at Deck Level 13 and spent all my Runes at Level 10 or 11, focused on Druid just because I wanted to see if the Growth was capped at any point.
Main earners are Mirror-ing Growth 14 Druid and Light Gain 48 Golem with Amass 9. Got Wanderer because it seems good, but didn't buy any other Cards because they just seem useless for my strat since I didn't Prestige to get Destruction.
Now fighting the Abyssal Void repeatedly and played for less than 12, or even 6? hrs, I think.