American thinking of changing citizenship to Japanese. What does investing look like for me?

As the title says, I'm American, have a small nest egg of a Roth IRA, but also don't really see myself leaving Japan, so I've considered naturalizing and simply going for Japanese citizenship. I believe I have to pull out of my Roth IRA, which will have some fees which is too bad but kind of unavoidable. What platforms would be good to look into if I do end up going through with it and becoming a Japanese citizen?