The phrase "on the" can be replaced by several synonyms for a different range of contexts. "On top of" is commonly used when referring to something that is physically above another. Similarly, "above" and "over" convey the same idea as "on the." "Upon" is a more formal synonym that can provide a more sophisticated tone. For a casual and conversational tone, "about" and "around" can be used to describe a general vicinity or concept. "Regarding" is another option that can be used to introduce a topic or subject. Lastly, "in relation to" and "with respect to" can be used to compare or contrast elements within a context.