A very weird puzzle without a forced win

So, out of ~2500 puzzles I took here, this one is by far the weirdest.
lichess.org/training/67948

Normally, there is always a logical explanation for engine evaluation, even if it isn't immediately clear, but here I was at a loss for hours. I ended up solving it just by playing the only sensible line that I saw, even though I couldn't see it to the end - after a few moves I couldn't figure out what to play at all.

***********SPOILER*************

Turned out the Nxc4 line was indeed correct, only Stockfish ends up sacking the queen in response, which I simply fail to understand. Now, if I play the only reasonable move that I saw in response - Qc7, I can go TEN MOVES in best offered by engine analysis with +6 eval and nothing is remotely looking like a clear win. Well, white are 2 pawns up and black are in a very difficult position, but basically what you did is won a pawn and obtained an attack which Stockfish itself seems to be rather unsure how to finish decisively.

Just to sum up - in my head I went up to Qc8 after which I could no longer see anything forcing and looking at the "solution" provided no answer either - for the first time in my experience.

Thoughts, comments? What am I missing?

I have always insisted that Stockfish's evaluations are meant for debugging and don't have some deeper meaning (except for mate scores). Regardless whether it's +3 or +30 the key questions are:
* What are White's best moves (and as a human, how do we evaluate them)? I don't know.
* Does sacrificing the queen for 2 pieces plus an exchange put up greater resistance than Qc7 Bf4? I think the answer is yes, because if you go another 20-30 moves down the main line Qc7 maroons Black's king in the center of the board and White has no weak pawns and White's king is safe. That doesn't make this an instructive puzzle, but it's certainly a challenging exercise.

This behaviour start to be the norm the higher the puzzle rating is. Computer loves to drop pieces when losing in complex positions... So, often you can luck out the first move and capture the free piece.

This is by far the biggest flaw in lichess puzzles.

This is actually kinda similar to lichess.org/training/79822 which also lacks a forced mate (but a clear initiative).