It would be important to be able to hide the outline of the text frames, through the "view" menu, just as it is possible to hide the guidelines, rulers, etc.
Go to the Text menu > Paragraph Text Frame and disable the "Show Text Frames" menu item to hide text frames in CorelDRAW:
To add this command to the View menu, you can use the UI customization features in CorelDRAW on Windows, accessible through the Tools menu > Options > Customization...
You can search for "frame" to get the "Show Text Frames" command and then drag it to the place you want to access it from in the application UI.