And there is no legitimate basis for them claiming that it meant them retroactively.
That's just them trying to put their claim of being the source of Scripture and spiritual authority beyond any doubt, and considering the history of the RCC, there's no reason to suspect or conclude that they are God's instrument on this earth.
The name “Roman Catholic” was a pejorative invented by English Protestants.
Since that “designation” did not come about until many centuries later and was used by Protestants and not the Church herself, that is of no consequence.
Funny, I recall a post earlier where you confirm the ancient nature of the Catholic Church.
There is no time when “The Church” ended, nor will there be.