The Elo ranking for the bots is mostly a made up number; a 1200 Elo rated bot does NOT play like a 1200 Elo rated human. Or even a 500 Elo rated human. The bots blunder in much different ways that a human would and humans play things the bots never would.

Also, what time controls do you use? Are you playing 10 minute games against humans but no time control against the bots? If so try longer games against human opponents, or set the time controls for games against the bots. The bots will never run out of time, but using a time control is a good way to practice making good moves under a time constraint.