Possibly it would be more practical to remove miniatures of windows entirely and have icons of the windows open instead. That would make moving windows between workspaces easier, like it already works with the icons in the thumbnail caption: it is easier to comprehend and manipulate icons of the windows instead of illegible miniatures of them. The fact is that with icons of windows as in the caption the miniatures of the windows become unnecessary and occupy the screen space for no reason.
Below is the workspace switcher from Patheon DE for reference of that I mean by my suggestion.
Possibly it would be more practical to remove miniatures of windows entirely and have icons of the windows open instead. That would make moving windows between workspaces easier, like it already works with the icons in the thumbnail caption: it is easier to comprehend and manipulate icons of the windows instead of illegible miniatures of them. The fact is that with icons of windows as in the caption the miniatures of the windows become unnecessary and occupy the screen space for no reason.
Below is the workspace switcher from Patheon DE for reference of that I mean by my suggestion.