The phrase “on the surface or overall” implies a general or superficial view. A synonym for this could be “superficially and generally”. This combination emphasizes that the observation is made without delving deep and is a broad assessment. For example, “Superficially and generally, the project seems to be progressing well, but on closer inspection, there are some issues.”
Another synonym is “at first glance and in general”. This phrase also indicates an initial and overall impression. For instance, “At first glance and in general, the new product appears to be innovative and useful, but further testing is needed to determine its true value.”
“seemingly and overall” is also a good synonym. It suggests that there is an appearance or perception from the outside and an overall assessment. For example, “Seemingly and overall, the company’s financial situation is stable, but a detailed analysis reveals some areas of concern.”
All of these synonyms for “on the surface or overall” help to express a quick and broad view without going into great depth. They are useful when you want to give an initial impression or a general assessment before delving deeper into a topic.