Preferences window too big on Macbook

Hello community,

I'm new to Adobe world and I'm taking some Adobe Ai courses. Thing is when I open the preferences menu to edit the UI, be it scale down the icons or change the interface colour, the window pop up itself is too big and won't let me resize it. 

I try to scale it down by dragging the corner but it makes that dull sound that the window cannot be selected. I can move it around and I actually have to because it's too big it goes off screen. Is there a way to resize this? It's riving me insane.

Thank you

(Also additional question, is there no UI scaling in Adobe Ai 2021??)