This puzzle is called extreme for a reason. In addition to naked and hidden singles it may require 48 other steps to solve. The exact figure will depend on how you approach it.
The puzzle should only be attempted if you understand the BUG (bi-value universal grave) solving technique.
If you type this puzzle into an online solver or app which does not know about this technique, it will probably give up and may even suggest that the puzzle has more than one solution:
