I was working in a two screen setup and moved my toolbars to the 2nd screen to have more space on my main screen. Later I opened QGIS with only one screen and all my toolbars were gone. I have been able to recover some toolbars by going to Plugins > Python Console, and typing the following:
However, I don't know the specific command for all the toolbars I'm trying recover. I'm still looking for the Data Source Manager Toolbar, DigitizingTools, Label Toolbar, Map Navigation Toolbar, Plugins Toolbar, Project Toolbar, QPackage, Raster Toolbar, Shape Tools Toolbar, Vector Toolbar, and Web Toolbar.