If you lack knowledge, you could always learn - there are plentiful resources online. The built in multiplayer requires learning as well if you are not very familiar with it. If you're making something with any significant concurrent user count, it is highly recommended to utilize a suitable back end service that can handle it like Colyseus. Photon seems to be a popular choice as well.
If you're set on using the multiplayer plugin, it does have the ability to run a central dedicated host by simply distributing clients that can only join as peers, while you run and manage the copy that runs as a host on a server of your choice.
Again, developing a multiplayer game in general, with or without the plugin, will take significant effort and research. It can be beneficial to learn how to use the most suitable tools from the start, given that you'll need to study regardless.