Macbook Air M2 is fully charged, I close the display, in 2 hours 60% batter left, in few hours zero ... so completely unusable. What can be going on and how to fix it ? Can it be HW or SW problem ?
Your lid sensor may require to be aligned. Check with the local Apple store. That is, when you are closing the lid, the display may still be full on and consuming high amounts of current for the backlight LEDS - as noted by the post above.
Most likely some kind of software conflict. Go through your processes and startup apps and see what is running; uninstall or deactivate anything that isn’t needed.
It could be a combination of things. Going from 100% to 60% in 2 hours if the screen was off or not is unusual. What is the battery health on the battery? I would do some basic troubleshooting like a few users have already suggested, and beyond that I would talk to Apple.