Let’s get real: you’ve built a toy prototype. The real business use case is more complicated as you’ve discovered because there is team and budget and process allocated to the current solution. Your solution is maybe 1/10th of the current solution: no team, no budget, no process, and a nice demo.
Acknowledging that, you have a bunch of really bad options and few good options.
The absolute safest thing you can do is to keep it to yourself, and to use it when you can to make your own job easier. If you’re able to find time to use the tool to load your own data because the team that owns this process is overloaded, then they’ll appreciate the relief, so long as your tool doesn’t break or violate their standing policies.
The best advice in this thread is going to your manager and asking for time to develop and demo an automation solution. No one wants to hear that you’ve already built it because that raises thorny political and management questions. The best you can hope for is a sanctioned meeting where you can demo the capability to your manager and the manager of the other team.
If you’re fortunate enough to get authorization to proceed, make sure to tell everyone that your solution only handles the common simple cases and that the tricky special cases still need manual review- an 80% solution. The achieves two goals: allowing you to get away with having bugs, and allowing the other team to believe that they are more specialized and, hence, more valuable now with your solution than before.