I don’t know about the Dutch end .. But the IRS taxes as income any distributors from an LPRs retirement account overseas. For this reason, we got everything out of our Australian investment accounts and retirement funds, and sold out house.. before we entered the US on our IR5 visas .. We moved everything into our aust bank account then moved it as cash to our US bank account using OFX once we were in the US. We were fortunate that we had both reached retirement age and so there was no Aus tax payable on the cashing out process. But, oh, the complexities of the IRS are deeper and darker than the USCIS