No it’s not foreseen in the app, but there’s an easy way to do it by yourself:
Go to the Startup folder where you added the shortcut to FileVoyager
you can go there by navigating to %AppData%\Microsoft\Windows\Start Menu\Programs\Startup in your favorite file manager, or a more recent alternative which consist of navigating to Shell:Startup
Normally, you should have a shortcut to FileVoyager. Right click the shortcut and open Properties
In the Properties windows, change the value of the Run field to Minimized. Then apply the change.
From now on, FV will start up with a new Windows session, in minimized.
On my side, I add a to do list item in my backlog to implement this feature out-of-the-box
P.S: When launching FileVoyager from the Windows Start Menu there is another link to FileVoyger in:
C:\ProgramData\Microsoft\Windows\Start Menu\Programs\FileVoyager which has to be adapted in the same way you described as well, if one starts the app from there…