If you still haven't visited Blizzard's brutal but surprisingly fun version of hell in Diablo IV, now is a very good time to do so. Blizzard has confirmed on X that the game currently is free to play on Steam ("up to level 20") with everything unlocked - and will remain that way until November 28.
To make things even better, there is also a 40% discount on the game during this period of time, and you will of course get to keep your save file from the trial to the full game if you end up buying it.
See you in hell, it will be fun, we promise!