DH has been working on a software product in his spare time for about 18 months (he earns a lot freelancing, so he was able to take a few months off to work on it during lockdown and to take some p/t contracts to give it some more time). He has done research of speaking to mates in his field (both who understand the programming and people who might use the product) about it and is fairly sure he has something that does something a bit different to anything on the market. These are friends who will be frank and honest, so it sounds like he is on to something - it is boring and technical and addresses a problem he has noted in his professional experience.
I've said to him that at Christmas we should have a chat about where he goes next and when he tales the plunge to getting investment to finish it off. At a certain point, as far as I can tell, he'll want some capital behind him to get some others on board working on it to create a viable product. He's spoken to some contacts and has others in mind he might sell it to. A friend who knows a bit about development has said it's good that he's got it fairly developed as the more complete the product, the greater stake/control you have in it once investors come in.
I'd be interested to know what experience people might have of maybe getting investing in a product and launching it - or being the partner of someone who has!