How can I make a server for a game like league of legends or brawl stars?

Hey! So I developed the prototype of a multiplayer game with MLAPI, and I can play it locally if I manually start the server and connect via wi-fi with my local IP.

I want to host the game servers myself, the same way LOL, Brawl Stars and Clash Royale do, and I also want to control the matchmaking, rankings, etc.

I think know what I have to do, but I don't know how to do it. I need launch a game server instance for every match, and I need a database that does the matchmaking and stores the rankings. But I have no clue of how to actually do it.

How can I access my computer from an outside network?
How can I automatically start a server game?
How do I then make my clients from around the world connect to this server game?
What technologies/techniques would you use?
I would like to do this myself for a start without AWS or anything like this because my budget is 0 xd.
Any tutorials that can help me?

The more specific you are, the better, thank you!