This is an incredibly hacky workaround, but I was getting so annoyed with mashing the mouse button that I wrote a quick autohotkey script to press the 'next action' button with the spacebar:
#ifwinactive Warlock
coordmode, mouse, screen
space::
MouseGetPos, storedMouseX, storedMouseY
click 1796, 820
MouseMove, storedMouseX, storedMouseY, 0
Copy/paste that block into an .ahk script file and run it. It simply moves the mouse to the button and presses it once, and instantly returns the cursor to the position you had it at each time you press space. This also means you can hold down the spacebar between turns to skip through all enemy moves quickly.
Note that the click position is relative to a 1920x1080 res, if you're running something different you'll need to change those click coordinates