When engine is hot transmission will not engage reverse

It sounds like the transmission is going bad but I would try to replace the engine coolant temperature sensor which could be shorting out when warm causing the issue.

Here is a guide to walk you through the steps and diagrams below to show you how on your car:

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

Check out the diagrams (below). Please let us know what you find.

Cheers, Ken