I would suggest talking to your manager. But don't let on that you've already built the automation - they don't need to know that. Instead, say you've observed

I would suggest talking to your manager. But don't let on that you've already built the automation - they don't need to know that. Instead, say you've observed something, that you think you'd have the skills to automate it, and if the business would be interested, and would they compensate you if you could indeed improve the process? This presents no threat to anybody and allows you to gauge reactions.