So assuming you have a windows .bat boot file, example: java -Xmx5G -Xms5G -jar paper-1.18.jar nogui
You would just replace the "java" part at the begging to whatever your java version path is, example: "C:\Program Files\Java\jdk-17.0.1\bin\java.exe" -Xmx5G -Xms5G -jar paper-1.18.jar nogui
You can have multiple versions of java installed on one computer.
It'll allow anyone to join with any username if you turn it to offline mode. It's also illegal to pirate games, which is the only reason you would use a server in offline mode, besides maybe for a Bungeecord setup but the proxy would handle checking valid accounts.
Dragon Wars, you're able to control dragons and hit the space bar to shoot fireballs. Objective, kill all other players riding dragons. You could also have kill streaks that summon lightning on another player or a group of Vex that attack a player.
The ability to have users download mods simply by connecting to the server or just being able to store custom model data in blocks and entities, that would make things simple.
I wish I could snap my fingers to instantly create any type of digital or physical currency in any time period out of a very small amount of air, in my universe, forever.