According to a recent report by Bloomberg’s Jason Schreier, an early build of Diablo 4 has been already sent out to a number of testers close to Blizzard Entertainment.
Previously, there was an opportunity to pre-register for the Beta version of Diablo 4 through the game’s official website, which is not available anymore.
So, if you had already signed up, you will still have a chance to play the game before its launch.
Regarding the fact that Overwatch 2 is going to launch later this year, we can probably expect a late 2023 release for Diablo 4.