Obviously, the whole 'woohoo Xbox #1' stuff regarding Diablo 4 is nonsense. You just launched a less than year old AAA game on your sub service? Yeah, no shit you're going to get a sudden surge of players.
The truth though, in contrast to many of the posts here, is that Diablo 4 was a big piece of shit, but is now in pretty good shape. The new patch is looking really good at clearing up some of the remaining issues with itemisation, and the endgame is stronger than it has been since launch. If you own it and it's sitting in your Steam/Battle.net library, constantly reminding you of the money you wasted, it's a good time to give it another try. It's not as autistically complex as PoE, but it's a lot more polished and user friendly than Last Epoch. I enjoy it a lot.