I would have just been trying to get it from N gacha pulls instead of explorations.

The 30 day SR girl Count as getting a SR-Girl as do event rewards. So select an get a SR girl quest before claiming rewards.
Reweal + SR-Gacha also is also good to keep in reserve it you are unlucky and need a last SR-girl to get Ex-Wild.
When going for Ex-Wild make cetain you got more than enogth to get all the SR-girls it is not fun ending with 2 out of 3 SR girls.