How does a game like Roblox work?

Hi,

I am a indie dev (In Roblox and in C++) and I dont even know if this is the right subreddit to post on but ive wondering how a game like Roblox works. I am pretty experienced with Roblox as Ive been playing since 2018 so I kinda know how the platform works (Servers, Clients, etc). But how does it work behind the scenes? I googled it and it said something about TCP and UDP or something.

Ive been wanting to code something like Roblox (As a fun little hobby and probally not gonna release it) though I want to learn about how the servers could work. Could something like Cloudfair tunnels work?

If anyone could help that would be great or even just tell me which subreddit I should post on.

Thanks!