There are some difference in client wifi interfaces (STA) and access point wifi interfaces (APs, like you'd find on a good router). For example, some wifi interfaces don't have promiscuous mode, or can't scan while maintaining an active connection, etc.
It's like the difference between softmodems (aka winmodems) and full hardware modems. I know there are some projects that use Raspberry Pis as an AP, and it could do like 10 devices stock and 20 devices with firmware changes. Even a low-end router could handle more clients than that.
There is a Jackbox game called "Talking Points" that's like this: the players come up with random ideas for presentations, your "assistant" (one of the other players) picks what's on each slide while you present: https://www.youtube.com/watch?v=gKnprQpQONw
You only need $25-30. It'll be locked to a carrier, but that doesn't matter and is perhaps preferable (no monthly fee for a subsidized device) if you are able to use wifi. There's an ETA prime video which explores using a 2025 Moto 5G as handheld game console: https://www.youtube.com/watch?v=5ad5BrcfHkY
tl;dw it's quite capable for the money and would could easily get on social media apps/sites.
You can have a multiuser system but that doesn't solve this particular issue. If they log in to what you claim to be your primary account and see browser history that shows you went to msn.com 3 months ago, they aren't going to believe it's the primary account.
Miguel de Icaza is kind of a legend, I know him most from his work on Mono and Gnome. Whatever he works on today will likely be part of a stack you work on in a few years (at least that's my experience).