In the meantime, I made a button that runs a python script (.pyw to hide the cmd window) to restart Opus using its API as described here:
Script:
import psutil
import subprocess
# Define the path to the Directory Opus executables
dopusrt_path = r"C:\Program Files\GPSoftware\Directory Opus\DOpusRT.exe"
dopus_path = r"C:\Program Files\GPSoftware\Directory Opus\dopus.exe"
# Define startup info to prevent a new command prompt window from being created
startupinfo = subprocess.STARTUPINFO()
startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
# Find the Directory Opus process
dopus_procs = [proc for proc in psutil.process_iter(['pid', 'name', 'exe']) if proc.info['exe'] == dopus_path]
# Tell Directory Opus to exit
subprocess.run([dopusrt_path, "/CMD", "Close", "PROGRAM"], startupinfo=startupinfo)
# Wait for Directory Opus to close
psutil.wait_procs(dopus_procs)
# Restart Directory Opus
subprocess.Popen([dopusrt_path, "/runopus"], startupinfo=startupinfo)