There is a chance that AUVAL -1 error and Logic’s arm64e false detection happened because of mistakes when building my AU plugin component - i experienced unpredicted behaviour on Intel also, if project folder was not properly cleaned before building for another architecture. Now i always manually delete existing plugin and Xcode build folder, then clean project folder in Xcode and then build.
Regarding Xcode settings, i changed some minor things which i personally don’t believe could cause misbehaviour on arm64 - for example, setting compiler language standard and library to “compiler-default”, setting deployment target to 11.0 etc.
On the other side, I removed OpenGL and QTKit frameworks from Xcode project, which i believe could be important.
Currently i don’t have arm machine in front of me, so i can’t really try preferences one by one and find the problematic one(s). Will do when possible.