You can now add "initial_volume" to the settings.json file and set it to a number between 0 and 100. Here is the new setting in an example snippet from settings.json
:
{
"polling_rate": 200,
"gain_min": -60,
"gain_max": 12,
"initial_volume": 50,
}
If added to settings.json, the program will set the Windows volume to this value on launch (and by extension any bound Voicemeeter strips and subs)