P85 if non-resident landlord subject to self assessment

I am planning to leave the UK in the current 2024/25 tax year. I will be renting out my property, and HMRC has already approved my NRL1 form. I have read that "You do not need to fill in the P85 form if you are sending a Self Assessment tax return for the tax year that you leave the UK.", which will apply to my circumstances. However, I am not able to send (or register) for a self assessment tax return until after April 2025. Does it mean I still do not need to fill in the P85, or will I have to? If Yes, should I mandatorily submit the form as soon as I leave the country, or after the end of the current tax year?

Hi,
If you are already approved as a Non Resident Landlord, then you are already set up for self assessment for the tax year 2024 to 2025 and a notice to file a tax return will be issued to you after 5 April 2025.  
As you are a Non UK tax resident, you will need to complete a paper tax return, as the whole tax return including supplementary pages must be submitted in the same format at the same time.  The paper tax return will be made available after 5 April 2025 at Self Assessment tax return forms.
You cannot use the online HMRC version, as it does not include the sections for residence.  
If you have a government gateway user ID and password, you can buy a commercial tax return from the list of approved providers at Commercial software suppliers for Self Assessment and use it to submit the commercial online tax return.  
This option comes at a cost.
Thank you