And over time you could even offer a hosted/paid SaaS option, if there seems be interest in that and you have more time and resources available to sustain that.

From the perspective that you'd refine this project over time (as you already have), I don't think you should worry too much about how the code and architecture look and are right now or people's reactions to their current state. It'll grow, change, and improve as you do. And others' reactions can help you grow.

> I spent the last 6 months rewriting the architecture for multi-tenancy, overhauling the UI/UX, and adding productivity and compliance algorithms.

Separately, I think it could be really good for you and your career to document somewhere online (even just a blog) some of your thinking/decisions regarding these spaces. And it doesn't need to be too formal, just lay out your thinking.

Your post here is pretty great as an example of your communication skills - which I've heard are highly appreciated/valued in CS -, so you've got the skills, and it'd be great for you to have more public proof of that.

Entry level engineers on their own are not expected to produce flawless code let alone architecture. That you achieved something that ambitious in the first place will be a mark in your favor for most hiring managers.

Just check your contract and IP agreements first to make sure you actually have the right to use the code, since the way you’ve phrased it makes it sound as if you adjusted the company’s code rather than rewriting it from scratch after your role with them ended.