They make a Power Commander for the 790 but it seems as though Dynojet doesn't really support their map for it. I've tried downloading the file but it always says "file not found". According to Rottweiler, the PC5 will work and tune the bike for everything besides the "closed loop" portion of the map as the stock o2 sensors will undo the changes in the map. Rottweiler solves this by offering o2 delete plugs. This eliminates the data from the o2 sensors preventing the ECU from trying to correct the ratio. However, doing this results in the check engine light. If you can live with the light being on, then the PC5 will tune just like it does on every other bike. Rottweiler has a few videos explaining all this. They also show power increases on a stock bike, open muffler, and decat with open muffler.
I'm currently working on a solution which hopefully results in no check engine light and utilizes the stock o2 sensors.
2019 KTM 790 Duke