Thanks for the explanation. I hope you understand I’m saying the following with good intent.
Let’s leave aside for a minute the overwhelming odds you face as a non-traditional international student seeking full aid. Let’s say you get in, with sufficient aid. And later you get into a fully funded PhD program. What next?
You say you want to do research. To me, that means academia. It is extremely competitive to get a faculty position, and in your case you will also need the university to sponsor you for a work visa. For them to go through the cost and effort of doing that, you will need to be a far stronger candidate than all the other American PhDs applying for those same positions.
Alternatively, you might say you want to find a research position in the industry (not many exist these days in your field, by the way), but again you will need sponsorship. You will be in your mid 40s by then, and I would love to say there is no age discrimination in hiring because it’s against the law - but having spent 2+ decades in corporate America (in tech and finance), I would be lying. The odds will again be overwhelmingly against you.
My point is: for your plans to work out, a lot of low probability events have to all come through for you. In other words, bluntly stated: your chances are nearly zero. Is pursuing this plan the best use of your time, energy and money? If you want to firm up your CS knowledge more formally there are plenty of resources - books and online courses for example, that are easily accessible and relatively inexpensive. You can also do CS research on your own because for the most part you don’t need a lot of infrastructure or investment. You don’t need a college degree to be successful at your age and with your experience. And you certainly don’t need a US degree.