Can you implement multiplayer + microtransactions for existing Steam game?

I need a partner or contractor (for equity or for money) to implement multiplayer and microtransactions in existing Steam game: Celestial Creator.
The goal is to make something like Fortnite + MInecraft
I am open for reasonable partnership of any kind.
The project is located in Sofia, Bulgaria, Eastern Europe.

Yes, I will assist you with all aspects of this implementation, providing practical access, security, and functionality. As it’s on my development track right now. Message Thank You.