Leaving Japan – Financial and tax questions from someone with brain issues

Hi,

Someone recommended I post my questions here. I'm leaving Japan before the end of the year. I have to leave because I have cognitive impairment and have difficulty understanding things. I'm moving back to the Netherlands.

That also means I can only understand simple answers and not long paragraphs, though, so I'd really appreciate it anyone could help me like that, since I also don't have anyone who can help me with this.

*1. Income tax declaration for 2025: the tax office said I cannot do this before I leave because I can't get my withholding slips until next year, but they told me to call their English number for details and that person said I don't have to do it at all if taxes are deducted from my paychecks.

Taxes are indeed deducted from my paychecks, so I guess I don't have to declare taxes, but is it worth it in case I get a refund? How do I know if I can get a refund?

*1a. Someone else said that I don't have to file soon, that I can wait until I'm more settled. How long can I wait?

*2. Transferring yen to the US and to the Netherlands with SMBC Prestia Multimoney account (they'll let me keep my account open for 6 months after I leave). Prestia has this thing where you can convert yen to USD and EUR.

Is it better to do that conversion then transfer USD and EUR abroad, or should I just transfer yen to my foreign accounts and let the conversion happen that way?

*2A. I'll have to get 8 million yen out of the country. I'd like to limit taxes/tariffs on the receiving end as much as possible.

Does it make a difference taxes-wise in the receiving countries if I transfer in installments? Is my idea below too complicated/doesn't make a difference?

*-Take 2 million in cash back to the Netherlands (mostly with the idea to take it with me when I visit family in their developing country)
*-Change 3 million yen into USD through Prestia's promotion then put those USD in Prestia's Time Deposit for 3 months at about 4% interest (minus taxes), then transfer the sum to my US account (over a period of 3 months afterwards if that makes a difference?).
*-Transfer 2 million to the US right away (or 1 million in Jan. and 1 in Feb.).
*-Transfer 1 to the Netherlands at some point.

Thank you for any input you may have!