There are several synonyms for the phrase "on a level" that one can use to convey the same meaning. Examples include "even," "flat," "straight," "smooth," "horizontal," "uniform," and "parallel."
Each of these words implies a sense of balance and stability, suggesting that something is firmly grounded and consistent. When used to describe a person, "on a level" conveys a sense of honesty, integrity, and directness. As such, synonyms such as "forthright," "straightforward," and "sincere" can also be used.
In summary, the key to finding appropriate synonyms for "on a level" is to think about the qualities that this phrase conveys and seek out words that express similar ideas.