First, and I cannot stress this enough, you need to find a non-comics venue of income that can be your career. It can be anything as long as it has regular hours and leaves you with enough energy and time to draw. I don't know anyone who recommends comics as a career field right now. Even the best and most famous comic writers and artists right now are barely scraping by, most depend on a spouse's regular income or on non-creative income sources.
Second, It may be the case that you can draw comics and make some money doing so. However, I have never met anyone that makes enough money from just comics to afford a pleasant lifestyle. Further, if you make money or recognition your primary motivation for doing creative work like comics, the real results will never be enough to motivate you to continue.
I draw comics because I cannot NOT draw comics, somehow it always comes back. But it is a hobby, not my primary career. When I was younger, I thought comics or related fields would be the way I would earn a living, but I could not be more wrong about my likely prospects. I also did not know about some other career fields that are much better paid that I also enjoy and am passionate about. Doubtless there is a career field like that for you, too.
Third, the chances of a non-Japanese person succeeding in the already oversaturated Japanese comics market are extremely slim. Would a novice barista from Baltimore be able to successfully run a bubble tea shop in Taiwan? It's not impossible, it's just very difficult, and the kind of person that could succeed doing that would already possess the skills needed to succeed right where they are.
Indie comics are booming in the U.S. right now, build your skills right where you are. If wouldn't cost you anything to make a script from your favorite manga chapter and then draw it yourself without referencing the original artwork, just to see how you'd do. Inkers in training trace pencils from their favorite artists and do their own inks over them. For penciling, copy your favorite artist's work (without tracing) and take some drawing courses, which are usually inexpensive and available anywhere. Post your results and make friends online. A year or so of diligent practice will go far.
There are doubtless some in-person art groups that you could find to get the kind of critique you want. If nothing else, there are almost certainly anime/manga enthusiast groups who would provide that in person feedback you want, and I bet some of them draw, too.