That block and pattern are lovely. I'm sure you can master it.
Does your sewing machine have a "pivot function" for sewing?. Basically, when you lift-up on the foot pedal, the needle stays down in the fabric and the pressure foot lifts. Some machines have it.
This lets you stop the stitching and move (or turn) the quilting piece under the needle area.
Next, are you using a foot pedal? Some machines have a button to start/stop the stitching and the foot pedal is optional.
Dome like a knee lift too. I haven't bonded with it yet.
The other options you might try is to make sure the fabrics are starched well. As in almost stiff as a board starched.
Go slow with stitching and you will get a feel for the stopping and turning. It's not easy but practice as you are doing now.