command that let you to set match to be bo(amount). Might be useful for dueler, so we dont have to type the score (auto show the score), automaticaly disable the mode when a player reach the win needed, and force other player to spec when they come to the room when the match still going on.

I like this idea. Both players set duel mod bo 3, during those games they lose their tcs like in a typical /duel mod, but after 3 wins a winner gets his and opponents tcs. Leave is a loss, spectating is only acceptable by agreement of both players or its unavailable at all, you can only pause the game during the duel, for example:
Siou vs Fake, duel bo3
/duel mod (amount of bo, in our example its 3) 20000 (TC)
Command fspecs both players and whenever both of them enter the game, duel starts. (Works like a casual duel mod)
Siou needs to brb, so he writes a command /pause but he needs his opponent's agreement, so his opponent also needs to write /pause

In case of 2-2 score both players can change a duel to bo4 by agreement and another command

After the duel, winner gets his and opponent's tcs

My English is bad but i hope you got my idea

Idk about the whole /pause thing but I do think this could be implemented in a clean way. Kind of like how clan wars are set up./Duel fake 20000 3
Dueling fake 20000 best of 3 or something?
But what if other people start joining the server? In aware of commands for that type of thing but it just sounds messy at that point