Just a point to consider: how long would it take you to recreate this work? My guess, not nearly as long as it took the first time. 90+% of the time in coding

Just a point to consider: how long would it take you to recreate this work? My guess, not nearly as long as it took the first time. 90+% of the time in coding, is figuring out the problem space in greater detail. Much of the rest is figuring out the best architecture to fit that problem space. Very little is typing and getting the syntax right. If you have to abandon what you've done, leave, and recreate a new version, would not take you two years. Two months? Less? Not saying this is what you should do, just that you consider what it would entail, if you handed the company your side project and then left to go re-create it from scratch, with all the lessons learned from the first time.