You cannot beat KataGo in an even game; even top professionals have to take two or three handicap stones. But high-handicap games are different from even games. KaTrain can weaken KataGo but it does not play human moves found in Asian server games.
Find positions from your games where KataGo says that you have a large lead. Set KataGo as the opponent and play from those positions.
There can be several reasons for the lead:
- You can have a running group that KataGo knows it can save, but can you?
- Or the opponent can have a weak group that KataGo can attack profitably but can you?
- Or you have a lead in territory and KataGo knows it can hold that lead, but can you?
- Or the opponent has what look like large territories but KataGo knows it can still play inside or substantially reduce them, but can you?
You can also play endgame against AI; if your win rate goes down, study the AI’s variation, but don’t expect to win.
Another idea: tell KaTrain to generate a game at move 200 that’s roughly even in score. Then try to find the best endgame.