You are way too fixated on what other people think of you. It needs to go if you're going to survive. Doesn't matter if your target living space is Japan or not.

Besides the Japanese are so effing conservative, and closed-mouthed about what they're thinking, even if some particular Japanese man/woman was jealous of your growing skills---they'd never tell you, and/or you'd never know anywayz. Forget about it.

There are TONS of American-Japanese artists, mangaka, doujinshi, seijinshi artists, ect---and they're doing just fine.

One example that I can think of, who's been one of my favorite for a very long time, maybe you know of him already?...is Adam Warren. Check him out on Google even!