Roblox updated their client some months back, and the anticheat didn’t work with Linux at all. However, it looks like they’re working on fixing this and the game is now playable on their very early access “zcanary” builds.
I suspect this Lemmy Steam Deck community has an older average age, and as a result may not have that many Roblox players. But the popularity of the game is undeniable and having it work on Steam Deck again will be great for a lot of people.
In my case this is good news as I used to play with my daughter which is using it on an Android tablet. And it’s always good to keep an eye on her as I play her games with her!