Withholding tax applied on stocks sold at Rakuten Shouken when no longer a tax resident?

Left Japan temporarily in 2020 right before Covid spread (I deregistered at the city hall before leaving), was not able to enter Japan with the lockdowns and my visa expired. Started working in another country. Been 4+ years since. Left some stocks in a Rakuten Shouken account as I plan to come back in the future with my wife (Japanese citizen). The account is frozen as I can’t carry out any transaction but can view it only.

If I inform Rakuten Shouken that I am no longer a tax resident and they sell my stocks to close my account, will they charge me capital gains tax or withholding tax? Current country of residence does not have capital gains tax on stocks and therefore no withholding tax.

I’m thinking what’s better. Sell it now and save tax (if they don’t impose tax on non residents) or allow it to appreciate till I come back. These are 99% US stocks and I am a non US taxpayer. If I ask Rakuten to sell now, I also need to see how Rakuten can send me the money as all my bank accounts are frozen too.