Hello tkbraaps,
The Akrapovic evo exhaust was made for KTM SDR 1290R 2020 model Specific you cant buy it form Akrapovic directly they will tell you to communicate with your local KTM Dealer.
KTM in order to avoid any legal issues implement to the exhaust map a peace of code to the bikes computer to check if the indicator lights are disconnected if not bike cant start (the reason was that you don't need indicator lights for track days

)
Now i strongly suggest to leave the installation to a KTM experience dealer because its not easy to remove half of the bike in order to install the EVO system and after that you must flush the dedicated map that comes only directly from KTM Service Tablet (tablet connects to your bike then tablet connects to KTM Server authenticate your bike and your EVO purchase , download the firmware and install it to your bike.
After that Error codes removed and the bike come back to normal mode back from the limbo mode.

Many ppl do the installations by themselves the instructions are pretty straight forward but you need a bit of experience in some steps.
for the complete restore of your indicator light functionality i have only one word to say Magic-box V1 or V2