LiChess puzzle 87510 has the following position:
[FEN "r1b1k3/pp4R1/2q3RQ/4p3/5P2/bP2P3/2P1K2P/8 b - - 0 1"]
The solution is
1...Bg4+, after which white has 6 legal moves:
1...Bg4+ 2. Rxg4 Qxh6, which is the computer solution (possibly followed by
3. Rg8+ Bf8),
2. Kd3, which is mate in 7,
2. Kd2, which is mate in 8,
2. Ke1, which is mate in 5,
2. Kf1, which is mate in 4, and
2. Kf2, which is mate in 4.
I feel like a human player in a tournament would not calculate the whole decision tree, and probably just intuit that
1...Bg4+ is going to win since black can continue with a range of powerful moves
Bb4, and at least one of them is with check, depending on white's response.
Question: How much calculation would a strong player (say an FM+) perform before playing
It's a dangerous move: black begins with an exposed king (with mate threats and a possible rook skewer) and queen attacked, and black responds by creating an undefended bishop. If the checks ended, black would probably lose.