Thanks for sending that.
So I was right about the top radius being fuunky. Those little dark edges were a good clue. The arc you drew wnet outside of the original corner. You can see that when you zoom in closely.
As cannelldb wrote, you can’t simply delete the edges, you would want to soften them. That’s done with the Eraser+Ctrl. Eraser+Shift hides edges.
Before you go farther change your Units from Architectural to Fractional, turn off Length Snapping, and set your precision higher than you’ll work in the shop.
From this:
To this:
When you draw the arc at the top watch for the magenta arc and the Tangent message.
then you should be able to do what I showed earlier for the inside corner.