Yeah, I made a post that includes pictures about this roughly a year and a half ago. UI should be decoupled from 3d video resolution. This is probably most likely accomplished with a UI overlay.
In that post, I was having the opposite issue as you are: playing with lower resolution which also made all my UI elements cover my screen obnoxiously.
By decoupling, you could make use of the feature in your situation as well: by scaling up the UI elements so your text and mouse can be usable.
To get past the old code, all the current UI could be hidden, and the overlay (including the mouse) could be layered on top.