It's great to see Frieren recognizing that she has changed since the last time she fought one of those monsters and illusory Himmel was such a bro to make it easy for her to blast him. I think it is a bit unfair to criticize Fern for freezing up fighting a monster when she did just fine against Qual when he was unsealed. Looking forward to seeing the party fully assembled and some action next episode.
Also, the OP has grown on me a bit since last week. It's not my favorite ever, but it is pretty good, especially paired with great visuals. The ED is amazing though.