Right, the player decides how the character thinks, acts, or talks. If an ability check is called for in a scene, the DM then adjudicates the outcome (which, notably, does not include then taking control of how the character thinks, acts, or talks). The DM can then start the play loop over where they describe the change to the environment and the player determines how their character thinks, acts, or talks in response to this change.
In fact, when I do get to play a character rather than DM, there is nothing that feels to me like nails on a chalkboard (we all remember chalkboards, right?

) than the DM describing my characters reaction to something. Damage, forced movement, conditions, all that is fine. But once they start narrating my PC's internal reaction - how my PC is thinking, speaking, or acting in response to some stimuli - I've become a passive participant watching the DM's story unfold. IMO, of course.