I want to make an FPS controller that feels realistic, like when you move you really feel that your character has mass. In Unity I would've done that with RigidBody, but how do I do that in Godot 4.3.1 with CharacterBody3D? I know that RigidBody3D is not suitable for character controllers. May anyone show me the direction in which I shall dig?
There's nothing stopping you from making your player a RigidBody3D if that's what you're going for, it's just CharacterBody3D is more common. You would apply forces and impulses on the player to move them around. You could use a CharacterBody3D but then you might want to program your own calculations for inertia and things like that which change their velocity.