My point is that none of the official announcements make reference to the nationality of the taxable person, only to their residence. So whatever you received from the NIFOnline regarding ‘only Portuguese nationals’ must be either incorrect or wrongly attributed in this context.
The determining factor for the tax rep obligation is your ‘economic activity’, which is described further in the cryptic language of AT’s official announcement from Jul 20, 2022 (see section 1, paragraph 5):
I personally intend to keep my tax rep for the remainder of their 12-month term as I already paid.
But I plan to remove the tax rep for my dependants as they certainly do not have any PT tax obligations at the moment.