This d/w fills, drains & heats but has no life from the main pump.
The cap looks ok in appearance (not swolen etc) & there are rusty water marks under the pump. I assume that the pump is shot , but as I’m on a learning curve with dishwashers I could be missing something.
I think your spot on with your diagnosis. If your listen carefully you would normally hear a hum from the motor as it tries to turn.
Not to bad a job. Go armed with a few jubilee clamps. As you sometimes cant resuse the old oetiker type ones.
(The thinner the clamps band the better.)
I find laying the dishwasher on its side is best but make sure you put a few towels down to catch any water.