I think OP is finding out there is no such thing as a digital nomad when it comes to banking/brokers etc. Unless your willing to just use banks and brokers in non-CRS countries like Puerto Rico etc then the concept is a myth that the uninformed fall for.
The account is gonna be reported to any countries address that was on the brokerage account during the year regardless.
That's it.
OP you are using some "old school" Digital Nomad Setup by just de-registering yourself from your home country and keep travelling - people were using 3-5 years ago without to many issues but due to having each year tighter laws within the EU this will be more and more difficult.
All your financial institutions like Banks, EMI's and Brokers are verified on your old home country - so while you are maybe fine with this - it's not fine for the financial institutions. Most likely you are from a reputable EU country and Citizen of it - so due to your Tier 1 passport the banks doesn't really care - however more and more regulation is coming - so expect that other financial institutions you are using actually will follow with what DeGiro is asking for right now - and even worse - in EU coutries with aggressive tax authorities like France & Germany having financial institutions within your old home country can even create substance that can then be used by the Tax Authorities to imply you are still having some economy connection / subastance to your home country - especially if we are going into 6 / 7 figure amounts you are hoding.
A straightforward solution would be (like mentioned earlier by colleague
@Gediminas ) to setup a Dubai Company with Residence Visa and local UAE bank accounts in combination with Interactive Brokers for example. The Dubai Company Formation grants you the Residence Visa and the access to the local UAE banks. Once the bank accounts are setup you can proceed with Interactive Brokers. This setup doesn't require the substance like we know it from the EU to get the bank accounts and Interactive Brokers is following straight the fact that you have your Company, Residence and Bank Accounts within the same country.
Furthermore Interactive Brokers is understanding the UAE as jurisdiction and they are fine if you are telling them you don't have any TIN and the reason for this is that the country (UAE) doesn't issue a TIN.
So Dubai could be your Business & Finance Center with the minimum requirement of being there every 6 months for 1 day - that's nothing compared to what you can achieve with this setup.
If you can't effort such a setup in terms of being every 6 months for 1 day in Dubai - you have to deal with the direct consequences - which is in the case of DeGiro account closer.