I'm sketching out a project that will cover many of these and I've developed similar projects before. If you need ideas, feel free to reach out. contactme at myuser.com
And you have the whole issue of “no one ever got fired for buying IBM”. Why would a company trust you for their HR needs over a well known company.
You mention you might use it internally for recruitment. That's a great starting point. Find one pain point (your itch) fix it with your tech. Then pick the next pain point, repeat.
In parallel your marketing effort should be identifying potential clients who are most likely to have the same pain points as you. Since you are dog-fooding your product, you can easily demonstrate how your product solves that particular problem. Again, repeat.
Build a simple AI-powered resume screener to filter candidates based on key skills or an internal chatbot to answer common applicant questions.
Once you’ve tested and refined it within your own business, you can expand the tool’s capabilities or offer it to other companies facing similar recruitment challenges.
Start small, solve a real problem, and grow from there.
Just go to bed, the itch will stop. No point staying up late nights.