In the recent episode of WeSayThings,
Valve made a lot of mistakes regarding Artifact and Underlords. No doubt about that. They officially ended development on Artifact, and word is, its the same for Underlords. That game was getting consistent, frequent updates but then suddenly stopped and hasn't got an update in over 3 months.
Despite this, we should be happy that Valve even want to expand the Dota Universe with other games. They don't even touch other franchises as much as Dota! Remember, after the release of Dota 2 in 2013, there wasn't a single Valve game released other than those in the Dota Universe itself. Only in 2020 they finally went back to the Half-Life franchise with a prequel.
Remember when Riot announced all those different games in different genres based on the LOL franchise couple years ago? Valve have been doing the same (only worse :P). But that doesn't mean we should lose hope. They are about to release an anime, and that's awesome. But we should hope and root for more Dota games too. I see the biggest potential in an RPG or RTS game. Its not likely that they'll make a shooter or fighting game based on Dota. But regardless, I'm hoping for something, and I hope they keep trying!