I think online, if you're already learning from online sources (autodidact), an undergrad experience is not going to benefit most applications of a CS degree.

One primary reason is, bereft of an intensely close relationship with the professor(s), they have zero reason to tailor the curriculum to your interests. You're a paying customer.

That said, aim for the Masters along with the undergrad. I feel there is a larger "perception gap" between a Masters candidate and a non-Masters, versus unskilled-but-talented against a CS degree +/- certs. You would be separating yourself into a more favorable pool by having the Masters.

I'll be honest: CS undergrad left in me a hunger that I didn't know I had, and a bit of regret at not diving deep into math. All the really amazing stuff that is CS-related comes after the academics: compilers, concurrency, operating systems, data structures & algorithms, constraints, theorem-proving, graphics, AI, etc.

So as long as you know CS will just get you to learning how to speak English, but now there's the real work of what to read, what to study, and what to "write" (code).

Best of luck :) I envy you are willing to give yourself a second chance!

(With family to consider, I would have also thought of just investing the money too.)