Maybe because it’s still an intel target ?
Ensure that Rosetta 2 is installed on your system. This allows Intel-based applications to run on Apple Silicon and navigate to your Applications folder, find the Arduino IDE, right-click on it, and select “Get Info.” In the window that appears, check the box labeled “Open using Rosetta.”
If that does not fix it, check if the OTA tool also needs the same selection (I don’t use that)