We are building a racing multiplayer game using Mirror and Unity and we've been able to successfully run the authoritative server on AWS-Gamelift and Playfab so far. Both providers are with the flexibility of running multiple server-builds and mapping with different ports.
So I think running multiple server-build for different matches on one instance is a bit expensive in terms of server usage as compared to running one server and managing multiple matches in different rooms. But overall it seems to be a safer option to go with since build crash and similar issues will only happen on one match and other matches (servers) will be running fine on the same machine and also it's a bit easier to handle and scale.
What's your opinion on this? It might be useful if you share any blog or resource to look at for scaling and managing servers on gamelift/playfab.