Moot

I would play for 8 dungeons a day to get the event-specific quests done. And that's it. Didn't like the low straight drop rate of items, when I played. Only if I really wanted a five-star child that appeared on the board, or if it seemed obvious I'm not reaching the desired board, then would I do the extra runs in auto-battle, 25 runs at a time, then synthesizing away the items.

Never dropped below 8k stamina though. It's one of decidedly weird parts of this gacha game. Rather active playing, but stamina regen is not a factor.

Thank you! I'll keep that in mind

I've been there. As mentioned 8 ND is enough to clear the boards, and 10 story mode at the very first level. Midnight Parade also consumes stamina so watch out for that.

Aside from that I think your stamina will go up.

Thank you! I will do that!

What the others said, do 8 times per day for the daily event missions and before the event ends grind stage 8 (hard) if you haven't finished all the stages and if your stamina can take it.

Keep in mind that rolling x1 is better than x5 because you can get the main reward on a single roll and then move on to the next stage without spending more than necessary ND currency. This way you could clear half the stages on the first day (or all of them if you're lucky) just with the amount of ND currency you get from first time rewards.