Have you checked to make sure the transmission fluid is both clean and full?
I attached the directions below, but they require a scan tool.
Also, is the check engine light staying on when the engine is running? If so, you may want to consider performing a scan of the can-bus system. CAN stands for controller area network. Basically, all the computers/modules are tied together via a few wires. This type of scan will identify trouble codes regardless of the module storing them. Here are directions and a quick video showing how it's done:
Let me know what has been done at this point, and can you explain exactly what is happening.
See pic below.
Image (Click to make bigger)
Thursday, November 4th, 2021 AT 7:54 PM