Convert a "browser application" from Windows to Mac OS

Hello, A developer coded a Windows application to open a website as if it was a standalone application, with Electron app builder. This application enables users to access a specific URL (without disclosing this URL) by clicking on a desktop application (with a .exe extension). At first step, the application ask users their username and password. It then checks if these credentials are valid. If they're valid, the application opens a VPN connection through OpenVPN to connect to a static IP VPN service. Then, it opens the target web page. It uses a specific user-agent (OS, browser, browser version, screen size, etc.). If it's not connected with the specific static IP provided by our VPN service provider , it won't launch the target URL and the application will close itself. When the target URL is opened in the application, some parts of the web page are hidden, some links are deactivated, etc. It's working like a charm on Windows but we need to convert this tool so that people working on a Mac can use it too. Note that even if the application is used on a Mac computer, the user-agent must be strictly the same than the Windows version. Best regards, Fab.