Make login invisible and localised - simplified
Make the login screen invisible after first login, with a last saved local login (a slider to enable this in settings) and options to logout/switch accounts. By doing such, you can also eliminate the pop-ups entirely and just get straight into the app. This would disable cloud saving so it would need to be a slider off by default in settings, but it would benefit those that like a clean screen on startup!
Stealth mode should also be an option while you're at it, just minimise straight to Windows Notification section on taskbar when PC starts up - even less popups.