Quick self-review of the match bugcat-jlt. Focus on three positions.
White was hesitating between A and B. If A,
Katago's main line is the following.
This seems complicated and I don’t really understand it.
The game variation is only 1 point worse for White, so is playable.
The marked intersection is an important point for both players, that both missed during the game.
However, the variation P2 R3 O4 P5 N3 mentioned by @bugcat in the post Playing "Sino-Tibetan formations" ("1-3-5s") - #19 by bugcat is 0.5 point better than the game variation and is easily understandable.
White made a bad atari (R15) which removed a liberty.
Instead the correct play was
This is a bit like in the game, except that White has an extra liberty so Black needs to sacrifice Q9, otherwise R11 gets captured.
Therefore after move 138, Black should have ataried at A and nothing works for White.
However, reading is complicated, there is a lot of aji.
White could have killed with...
B5. The reason is that if Black responds then Black may get one eye in gote, but White can then poke the other eye at G9.
Black’s shape has defects at A and B but Black can either connect or make two eyes.