The river in the south with the delta looks far too straight before it arrives at the delta. Not that there aren't fairly straight rivers, nor is there really anything wrong with your delta. But together they don't work to well.

Older rivers arriving on a flat plane tend to meander a bit, before starting to "delta" out at the mouth.

Straight rivers mean there's significant elevation and the water is fast moving therefore it is straight, which also signifies a "young" river. If fast moving, it should remain straight and no delta when arriving at the sea.

You'll need to decide if that is a young or older river. If you want to keep the delta, I recommend putting some side to side bends and turns before arriving at the delta.

Nice try, though, and otherwise perfectly "river police" legal.

GP