EACCES(permission denied) when tried to access /system/build.prop even after storage permission and SU

i’m new to kotlin and android i’m trying to read build.prop from /system for that i’m accessing root by using

Runtime.getRuntime().exec("su")

and i also gave storage permission(i have done all the stuffs needed to access storage that need to work on Android 10 like fileProvider and such things)

here is the code of accessing build.prop file

private fun filecreator(): String {
      val ensy= Environment.getRootDirectory()
      val filess =File("$ensy","build.prop")
      return filess.readText()
}

after it throws

msg: android.system.ErrnoException: open failed: EACCES (Permission denied)
stacktrace: java.lang.RuntimeException: Unable to start activity 
ComponentInfo{com.airbender.c2/com.airbender.c2.MainActivity}: java.io.FileNotFoundException: 
/system/build.prop: open failed: EACCES (Permission denied)

what should i do is there any way to access /system or my implementation is totally wrong

thanks