I can highly recommend checking out The Mirror! It's currently in alpha, but it's really cool to see what they have already accomplished.
The way it works in the Mirror is you create what they call "spaces"... And in your space, you build the game. They have "no code" visual scripting. And you can collaborate with other people in realtime in the space (which is really cool to experience).
I'm currently building a mini-game I haven't announced yet (consider this a teaser 🙂, more on this on a separate post ). It's currently in "build mode" but it's publicly available to drop in and check it out. And if you're lucky, you might actually catch me building the game and moving assets around in real time.
My Mirror game
Here's an interview with Jared (the founder) with a demo together with the host collaborating in realtime.
Might be worth checking out.