The Richter-Veresov Attack equalizes with Black's third move. This online, turned-based game is interesting as it shows the result of poor maneuvering in the middle game. The Richter-Veresov is a sound opening that surprises a lot of opponents, with many possible transpositions, including into a surprise French Defense.
Lesson learned: I did not see the 21.Ng4 alternative, thus need to expand my list of candidate moves, especially in difficult situations.
P.S. Dan Heisman said "Do as many basic (easy!) tactical problems as possible until you can do them very quickly. A goal might be 85%+ within 15 seconds.” Discouraging. After 3.5 months, my daily tactical exercises are showing 52%+ within 60 seconds, finding the correct solution 96% of the time! Probably one of the reasons why I don't do well in quick games.