Multiplayer is finally public for everyone.
It is now possible to join or create games in the "Multiplayer" section of the main menu.
Multiplayer allows you to play missions from the game and from the steam workshop in PvP and PvE.
It is possible to play with friends on the same team, and most of the features are now complete.
A few small details remain to be finished, such as the implementation of the voice chat (probably proximity voice chat), a better server list, and some other small fixes.
However, I recommend entering the Discord server where games and tests are organized together and where it is possible to report feedback and bugs quickly.
Here is the link: https://discord.gg/yS89tChxfK
Thanks everyone and have fun!