Hi!
The training at the Grid is only for In-Training level Digimon, Rookie and higher level Digimon need to win local multiplayer fights to evolve.
Sadly, I don't own an openAI subscription right now, ping @Yggdrasil at the GDevelop's discord server general channel so I can directly connect with you and inform you when I get a chance to test the code, it should work if you haven't changed anything (unless the structure of the response had changed (you can check this at OpenAI docs about API usage)), but I'll check it anyway.
There are new features that might be implemented in the near future, but it's complete. Please comment any bugs or suggestions. https://www.reddit.com/r/DigimonVirtualDevice
Thanks for playing the game.
https://digi-device-file.itch.io/digimon-law-of-the-jungle
A Multiplayer Digimon Action Game for up to 4 Players