I am playing on GUI x3 size (I am used to it) on 1920x1080 and the GUI of this mod is just too big with it, just look:

I have no idea if another mod is causing it, I sadly don't have time to check now.

use malilib fabric

As a genuine question as I know nothing about what it does in this case, how would that help?

As much as I would like to do something about this, Minecraft's GUI system does not really allow me to go about this in another way without having to write a significant amount of new UI code. For now I'll sadly just have to tell you to turn down your GUI scale when using the render UI
Cheers

Given that nobody has responded to this in quite a while now, I'll go ahead and close this issue as (at least currently) it's not something I can really fix
Cheers