Sounds like you’ve failed the CAA class one initial requirements, but would your eyesight meet the CAA revalidation requirements?
If so, a possible route might be to first gain an FAA commercial licence in USA which would then qualify you to be assessed to the CAA revalidation requirements (as you would be considered already a commercial pilot).
Best to confirm this with the UK CAA medical department, but this route was certainly available in the past.
If this is a no-go, I’d say just go for your FAA ratings and network like hell while you’re in USA. A friend of mine did this, ended up being sponsored for an H1B visa by his flight school, later petitioned for green card and is now happily working for a US major.
You’re young and have time on your side if it doesn’t work out.