21: The following sequence does not look good for B. But it's hard to say what would be better. M3, C3, F3... none of them look super exciting for B, but they at least have the advantage of not being outright bad.
23: Apparently not joseki; counter-hane is better.
N.B., 53 has a misclick variation
62: Seems to be a mistake in direction for W.
76: From this point the sequence on the right side seems to have a broad branching/ interposition factor. I'm not at all confident either B or W played soundly.
86: Seems to be slow for W. W didn't see Q4.
169: A bad and dangerous mistake for B? Giving up C14 gets sente to connect.
202: W took a mulligan on his ko threat, so there is a misclick variation.
212: Misread.
223: Misread. J8 is best for B?
247: A mistake for B: I think after this B loses his sente at A10...
257: Another endgame mistake for B? Probably worth two points.