Daily puzzle (#TkBHz) - what next?

I have a problem with current daily puzzle: lichess.org/training/TkBHz

Finding the solution is not hard but more interesting question is: once you go through the four move sequence and succeed, how exactly you are supposed to win? Because if white then plays 59. b7, black has IMHO a big problem. They could win the bishop via 59... Qa3+ but taking it would allow the b-pawn to promote (unless white blunders like 60. Kf7, of course). And other than that, white will move the bishop to d5 sooner or later and then the position looks like a standoff to me. Black can likely capture the b6 and g4 pawns but what then? Either the king or the queen will have to keep guarding b8 forever which would make any attempt for a checkmate quite hard. I don't want to say it's impossible but definitely far from obvious.

At depth 54, StockFish evaluates the position after 58...h1Q as -9.3 but isn't this just one of the positions where the engine fails to see the actual problem? The lines proposed by Stockfish do not seem to show much progress after all.

Thinking about it a bit more, this might work: pick the two pawns, block the promotion with king on c7 or b8, then use the queen to force white king to the a-file, move the queen to b4, bring the king closer and checkmate. But still far from obvious, in particular if white king manages to get close to the pawn on e4 and bishop on d5.

It is not easy indeed, but I think it is possible. Black might force the white king in the corner with the queen until white has to move a pawn on a dark square where the bishop can't defend it anymore .

Thanks, this sounds better than what I suggested in #2. With black king on c7, once the white king is blocked, white must either push a pawn or move the bishop away from the diagonal and either way, the defense falls apart quickly.