I do not have a last name, even in the national ID, but in the Upwork Profile, it is a required field. For the time being, I have put in a temporary Last Name. The question is if Upwork were to Verify my ID some day, would it affect that?
In cases like this we would suggest a user to use a formal salutation in the first name field (like Mr., Mrs, Ms.) and their name in the last name field. That would be unlikely to cause issues with adding your bank account. Thank you.