Plutonium

it worked? or indeed you need another files?

I have no idea what game_mod is, why do you need it?

You can play custom maps just fine as long as you install them properly. Both the Activision and the Plutonium folder works, just need to use the exe or to extract the map folder from it
https://plutonium.pw/docs/modding/loading-mods/#t4

It's not currently being worked on and I doubt it will ever be worked on. But if it's worked on one day it's in a long time as there are other priorities for now.

We have a Discord server with a channel to find players.
To replicate matchmaking you could find players there and join a server at the same time or host a custom game together

@SinicalX If you put images in the images folder it's client side modifications and will work everywhere unless maybe servers override them but I'm not sure about that, I'm pretty sure it just always work.

As for bans you cannot get banned for adding images in your game (camos, changing the HUD etc.)
https://plutonium.pw/docs/modding/loading-textures/