I also didn't go to college but did a pretty solid set of online CS and math classes while working as a software developer. I'd love to get a masters degree, and it would benefit my career quite a lot.

Auditing classes is fine¹ but probably not enough value for me on its own to be worth the time and opportunity cost. I'd want the degree and I'm fairly sure I have the skills and knowledge to begin a CS masters. But I can't get one without doing a BS first, which makes it overall just not worth the effort.

¹ Actually is it? I hear this recommended a lot but I don't know anyone who has audited a university course while not being a student. I tried it once at my local state school but it was an amazingly complex process to get signed up, and then I was told I could have a slot if there was ever an open one. There never was.