A little about Knights and Tournaments.

Correct, Attila used the same tactic against heavily armored cavalry when leading the Huns into battle. As we all know, Genghis Khan also used this tactic in his time.

Since the knights did not defeat Rus', it means it existed.

The problem is that the Livonian Order almost captured Rus'. After the Battle on the Ice, Alexander Nevsky clearly understood that Rus' was weak and could not resist the foreigners from the West, especially since Genghis Khan was advancing on Rus' from the East. Alexander quickly swore allegiance to him. So, as we can see, the knights were stopped by the Mongols from conquering Rus'.