Mate in 290. Myth or Fact?

Lately I saw a video from the biggest chess channel in Brazil. And, in the video, a puzzle was showing that there was mate in 290 moves, Rafael (Owner of the channel) wanted to know if this was true, and so he decided to put the stockfish at an extremely high depth, and he managed to make a calculation more than 1 trillion moves, but failed to find the long-awaited mate in 290 moves. Even though stockfish from such a deep depth couldn't see mate in 290 moves, I still found the puzzle extremely curious. Solving the puzzle is basically a maneuver, like a triangulation, of more or less 50 moves, and this may already explain why mate is so long, as 50 x 5 = 250. I would like to discuss this puzzle with you.

Here, is the puzzle

Observation: I put a few moves by Black for the stockfish to analyze, but after just a few seconds the stockfish said it was won.