How do I increase the loop cut amount on macOS Blender 2.8? How do I increase the loop cut amount on macOS? I have no where in the UI where I can change it.

Mouse wheel doesn't work, page up/down doesn't work, and numbers don't work.
You have to select where you want to loop cut first and click the left mouse button. Then a little menu titled "Loop Cut and Slide" should appear in the lower left corner that allows to adjust the number of cuts. For faster editing you can also use CTRL + R and the scroll wheel to adjust the number of cuts.