Blinking cursors break my concentration as well. I unchecked Blinking cursor, but the blinking resumed in the editor. I stumbled across a solution in Windows 10.
Control Panel / Keyboard / Keyboard Properties, and set the Cursor blink rate to None.
Right click the RStudio app, and Run as administrator. Uncheck Blinking cursor per usual, and the blinking should stop.
Let me know if this works.