I attempted to look for a .config file, but the only one available is a CLASS document which I'd have to decompile and seems to be quite a bit of work overall.

you have to go to the blur config (that much should be obvious) and to the list of blurExclusions add: "com.cobblemon.mod.common.client.gui.battle"

after having the same issue and finding no solutions online i ended up just searching the entirety of the cobblemon sourcecode for "gui" and found BatleGUI.kt which mentioned the above id right at the top
so similar issues should be able to be solved in a similar way