I know the thing you are describing, but the real bitch is that you're actually just describing the lowest effort default outputs. The help-desk assistant persona.

Sometimes speedbumps that deter the lowest effort infractions are sufficient but I don't think this is that time.

On a per-prompt basis, or via a persistent system prompt or SKILL, or - god help us - via community-specific fine tuning, LLMs can convincingly affect insane variations in prose styling.