I'm the founding CTO of a small startup, and I've been trying to find the business equivalent of your side project. Have you come across any modern tools for financial forecasting?
You can use fuzzy numbers to get varied output, and if you want to do MC you can use the API into your model to call it with whatever distributions you want and aggregate the output. But no, our UI doesn’t natively support doing a MC sim because the demand is frankly less than you’d expect. :)
The new kid on the block I like is cubesoftware.com . It’s priced rather affordably for a small business but maybe not a solo sized one
If I can't find something that works, this might be something I'm considering to build myself.