Tuetonic Knight tactics?

I beat the Barbarossa campaign on Moderate and now replaying on Standard.

I am ashamed to admit that I never used Tuetonic Knights the entire first playthrough. I tried to use them but I found them hard to use because they are soo slow.

So instead I relied mostly on paladins and hand cannoneers. I like cavalry for their maneuverability. I figured archers are inefficient because the lack of Thumb Ring upgrade.

I would like to give the Tuetonic Knights another chance but I'm just not sure how to best use them.

I read something on the wiki about coupling them with catapults but I had trouble pulling this off. Enemy cavalry would just run around my knights to ding my catapults, and square formation didn't work as it left huge gaps in my line. I think square is bugged.

Any advice?