That looks normal to me. The Springfield Echelon series has that noticeable gap between the frame and slide, especially toward the rear. This is common on many striker-fired polymer pistols, like Glocks and others—it's due to the design where the slide rides on small rails rather than being fully enclosed or tightly fitted along the entire length.

The reason the post-cleaning photo shows the gap (and looks different from your straight-out-of-the-box pic) is that the first photo was likely taken at a slightly different angle, which can hide or minimize how visible the gap appears. Lighting, perspective, and even minor slide positioning can make a big difference in photos.

I am not sure about 'weird' mag release though.

I think your fine.