YOUR ROBOT IS AMAZING! WOW!I'll second the wooden dummy. It will definitely toughen up the forearms and get your head in the right place for applying blocks and two hand simultaneous coordination.
Here's one I built years ago (who the heck is that kid in the video?!), lots of fun but the shoulders kept wearing out. Before that I had a simple padded pole with arms. Anything to get you used to dealing with opponent's arms instead of just hammering away on a heavy bag.
Still, between this and a bunch of other solo drills built on what formal training I managed, I was able to show up on sparing night and give a good accounting of myself. Any formal training helps tremendously if you take it to heart in your solo work. Having a frame of reference from actually being in a fight or several is also good for preventing a waste of your training time.