I was thinking e12 from everything combined. Else it would get rather nuts, I fear. Various idol bonuses would indeed apply, as normally from idols gained from purchasing levels. This new bonus would apply on all objectives (ruby objectives, dungeons, FPs, challenges, etc). However, the new bonus could only be increased by buying more talent levels and gathering enough Dungeon Points to unlock more Dungeon levels.
You like it if players try to get as far as possible on a run, right? Imho, this game has a solid core mechanic if you want to reward that. Levels purchased, areas unlocked, time spent… But it’s been lying in the dust, while bonus idols and percentage-of-current-idols have taken the spotlight. Let’s dust it off, because it’s perfect if going deep is what you want to reward.
For funsies, I did a FP today. It netted me 9,253,634,727,028 idols. If we subtract 9,253,612,143,007 from Bonus Idols, we are left with 22,584,021 idols (22,671,092 ...