If you install PySide/PySide2/PySide6, you don't need to install Qt as well.

Included with PySide[2|6] is QtDesigner, hidden in the distribution but available for use, and all the compiled Qt libraries.

The application created from that can be released closed source as using Qt under LGPL.

As for packaging;

Use PyInstaller, which creates a dist directory. Included in that dist directory will be everything needed to run your Python/Qt application.

Use Inno Setup/Inno Script Studio (https://jrsoftware.org/isinfo.php) to package that dist folder into an installer.

The end result will be a self contained installer which acts just like any other Windows software with an installer.

I use all the above to create and distribute Captain's Log (https://captainslog.scarygliders.net)