GE Dishwasher GLD5560L15SS won't drain

We recently bought a house. The prior owner had said that the dishwasher wasn’t cleaning dishes and arranged for a repair. The guy came out and turned the dishwasher on and looked puzzled since he had been told that it needed a circuit board and wouldn’t start. I told him I was told it wasn’t cleaning well, which appeared to be the case. He looked at the spray arms, said they were plugged, and suggested Dishwasher Magic, which I used that day.

Now I’m noticing that the dishwasher isn’t draining. It may have been that way, and I just didn’t notice it, or it could be new. I do not have an air gap or disposal. The drain line goes straight into the sink drain. I took it off, pressed start/reset, waited 30 seconds, and pressed it again. The dishwasher drained most of the water in the tub into the bucket I had. It was clear. I reconnected the hose to the drain, and repeated the button pressing, and this time, almost all the water was gone. The sinks do not drain slowly, so although I haven’t taken all the sink drains completely apart, I don’t think there’s a plug there.

Based on prior answers to GE dishwashers not draining, I looked for a piston/nut assembly, but my dishwasher doesn’t have one on the parts diagrams. Everything looks pretty clean on the bottom of the tub. I took off the lower spray arm, but can’t figure out how to get anything else off. I can’t find anything to unscrew, and I’d really not rather break something and upset my wife.

Any suggestions or help will be incredibly appreciated by my wife and myself.

Thank you so much.