There are a couple of simulator manufacturers who produce 3 screen push back simulators. The screen can be customised to show views of the stands and backgrounds at the airport of operation to increase the realism. It is also possible to show the view from above, the side, as well as from the tugs cab.
They can be set up to simulate tug and bar or towbarless push back tractors and aircraft types can also be specified. If you are at an airport that only handles narrow bodies then you wouldn't need an A380 or B777 simulated.
At a GHA I worked at the simulator was used both for initial push back training and also refresher training at stated intervals. There were a couple of stands with awkward push backs and these were obvious candidates to be in the database.
The visuals are good quality and we actually suspended 2 experienced push back drivers from operating tractors because they had some bad habits. They went through re-training and when we were satisfied they returned to the job.
There is some very good modern training available, but how many companies use it I couldn't tell you.