Think Kinematic Character Controller in Unity, except covers all current LTS versions of the engine with minimal manual labor. Has all the usual functions (look, move), and all user has to do is hook up an InputActionMap. Comes with an InputManager.

Basic version: looking, moving, optional jumping + sprinting (easily removed). Each subsequent version is built on this.

FPS version: includes fire control, basic weapon implementation, common interfaces (damageable, destructible), player death, example enemy

Horror game/walking sim version: basic object interactions with examples (object pick up/rotation, door open, etc), interactable interface, head bob, footsteps (basic sfx to be replaced, can literally just be tones)

Third person/full kinematic includes: zoom in/out, cinemachine inclusion for camera obstacle avoidance, first person toggle, common third person cinematic functions (zoom out in combat, zoom in when near interactable object, add cinematic black bars to top and bottom of screen, etc)

Yes, a first and third person character controller for Unity exists, but if you've used them, you already know their limitations. Common character controller problems are left completely unaddressed. Kinematic character controller filled this void, but it's no longer being actively supported by its developer. Also, for what it needs to do in most use-cases, it's also extremely overcomplicated and a pain to rewrite.