How to safely route a wide groove in 2x2?
I highly recommend using a pusher and gloves for this project. There are lots of &quot;brands&quot; you can choose from, or you can use another board to do it. You only have one set of fingers though, and keeping them safe is more important than any project.

If you will note in the above picture, the board is being pushed forward and into the fence. This is an excellent way to get an even cut and retain control of the board.
If you don't have a fence, you can clamp another board to the table and that will work almost as well
Once you have lined up and completed your first cut, move your fence back from the cutter 1/8th of an inch, and cut again. Then rotate your board 180° and cut again.

Hope this helps!