Does the proxy require a username & or password in order to grant access to using it? I know the one I use from proxyfish requires you to log in via a username and password to set it up however I just use proxifier and right click the osrs client and use the proxy on it that was as I'm not using CLI or stealth, I just use MM for personal use.
If you hop into the discord and post in the #help section over there, there will be more people technologically advanced than I am when it comes to this sort of thing who might be able to help and or point you in the right direction