Probably the easiest way to run it is with Vinegar, a Wine wrapper for Roblox. You can just install it from Flathub (or Discover on Steam Deck in Desktop Mode), make a configuration file in terminal to set it to Vulkan and then you're good to go after that:
mkdir -p ~/.var/app/io.github.vinegarhq.Vinegar/config/vinegar/ && { echo "[player]"; echo "dxvk = false"; echo "renderer = \"Vulkan\""; } >> ~/.var/app/io.github.vinegarhq.Vinegar/config/vinegar/config.toml
I know there's a launcher called Grapejuice that's very popular for running the game as well, but I don't know if there are any additional steps needed to get it to work.
I mean, if you're on the fringe of wanting to play things that are almost incompatible with the system, sure?
I don't really touch Epic, Ubisoft or EA. They don't really offer anything I'd deem fun. I played COD, I like CS and TF2 more. Lucky me. Roblox also looks like my definition of "jank", and it's never interested me. We have Gmod and Minecraft. All good here for janky fun.
I do have one tiny hole in my gaming portfolio on deck. Stalker: GAMMA. The only real viable method of installing it would be to install Call of Pripyat, then copy my GAMMA install from my PC's Windows partition. Doable, I'm just lazy and I've got more than enough to enjoy as-is.
But the zone will call me back soon enough, blin.