Hi, there is no setting to invert the mouse cursor. However, you can change the cursor to something more readable. Create a userscript or run the following from the console:
require('ko/editor').scimoz().cursor = 2
The number can be anything from
8 for a variety of different cursors (the default is
-1). Sadly none is an inverted insert cursor, but maybe you can find something that suits you. You'll have to have this code run for every document, which a userscript can do.