Please note that when playing local multiplayer, one Switch can support 2 players, so that means in order to play with 10 people you need 5 Switches. It can support a maximum of 12 players. Well more than that, at least 50 in Splatoon. Maybe you mean in person local play?
Unfortunately, Roblox is not available as an app or game download on Nintendo Switch or Switch Lite. As of January 2022, you can play Roblox games on PC, Xbox One, iOS, and Android only. Although you can open up Roblox.com via the browser on your Switch, you won’t be able to actually play the games on it.
Therefore, it is impossible to play ROBLOX on a 3DS, as ROBLOX has found it not to be a good idea to push a player application for that platform. Is the 3DS XL discontinued?
Since launching in 2004, Roblox started out as a web platform that was only available on PC. Travel to modern day, and players can instantly launch their favorite Roblox games across multiple devices including iOS, Android, and Xbox. So what about the Nintendo Switch?
At this time, you cannot get Roblox on Nintendo Switch, nor any Nintendo devices. Moreover, players cannot download Roblox on the PlayStation 5. Roblox is not available as an app on either the Switch or PS5, which means it cannot not be downloaded from either console's game store.
If you have figured out how to access a web browser on the Switch, then the platform itself might be accessible, but that's it. Either way, you cannot play Roblox games. For example, the Avatar Inventory may be accessible but the browser will prevent you from launching any games on Roblox, like Adopt Me or Arsenal.
Even though Roblox isn't available on Nintendo Switch, all hope is not yet lost. In May 2021, CEO of Roblox Dave Baszucki commented that Roblox support on the Switch, PS5, and the Oculus Quest "all make perfect sense," as reported by GamesRadar.