There is a qualitative difference between what it is like to be a human and what it is like to be a bat. You can't "get closer" to bridging a qualitative difference. Likewise, qualitative difference cannot be "less different." Those terms only apply to quantitative differences.

Additionally, learning additional facts about bats, such as that they create acoustic cognitive maps, doesn't tell us anything about what it is like to be a bat. That's literally the whole point of Nagel's paper.