A dedicated server is any computer that stays on and connected to the internet.
If you were using the included multiplayer plugin for peer to peer, all the server would need is to be able to open a browser. Any desktop environment running Windows，Linux, or MacOS can do this.
Would it need DB integration? Maybe. Do you need DB integration? You can build your own DB in an array. If all you need is a DB, you might not even need multiplayer at all. Each player can just communicate with the DB directly and not with each other. You can interact with a MySQL database through PHP with the ajax plugin. This database could be hosted on any normal website server. Or you can just save to local storage on the host machine.
Do you need remote access and control? Most desktop environments can be accessed through vnc software.
If you have no idea what you're doing, you're probably best off using a third party backend service like Photon or gamesparks or playfab ect.