orbstack provides a docker engine and sets the socket to point at that. It's a complete system, it's not "just a gui for an existing docker instance". Your issue is your flawed understanding of what Orbstack is and not understanding docker contexts. You can use Docker contexts to run OrbStack and Colima side-by-side. Switching contexts affects all commands you run from that point on, see: https://docs.orbstack.dev/install#colima

# Switch to OrbStack

docker context use orbstack

# Switch to Colima

docker context use colima