It's not just a graphic. Each leveplate design corresponds to a different type of leve. For example, all of the leves where you collect pages from the Necrowhatever have the same leveplate. All of the leves where you defend items from attacking enemies have the same leveplate. And so on. There's actually quite a bit of lore behind the different leveplates, but it's not made very clear in-game.

The challenge that requires doing five different leveplates means that doing Necrowhatever at five different level ranges isn't going to work, because it's the same leveplate each time. The goal of this challenge log entry is to do five different varieties of leves, not the same type of leve five times even if it's the same type at different levels. So, yes - botanist cannot complete this challenge log solely as a Botanist.

To the OP: The answer is to do a combat leve FIRST, and then do the four different Botanist leves. Won't help you this time around, as you've already done the four Botanist leveplates, but you can remember for the future to knock out a combat leve first thing each week.