I do like the idea of being able to hide the content browser while editing the map but personally I don’t use that feature.
since it seems like you are editing your blueprints and requiring a save you might prefer to have the old style where you can have your content browser on display at all times, you can do that by going to “Window/Content Browser/Content Browser (1/2/3/4)” … you can go a step further and dock it to the side by right clicking it and selecting “move to sidebar”, but that just puts you back to your original issue.
also “ctrl+shift+s” is a SaveAll shortcut