is there any way i could make it a longer distance?? by editing the mod or the server plugin?? or it has to be both?

Each player can change distance with a slider in the settings.

You can also configure distance presets in the plugin config.

# Voice distance
distances:
  - 8
  - 16
  - 24
# Default voice distance
# If 0 distance will be first element from distances
default_distance: 16

There is also voice.priority permission which allows you to bind a separate push to talk for talking in a higher radius which you can set with the /vc priority-distance <number> command.