“Roman Catholic” is an ENGLISH expression invented by Protestants - as shown in the OED.
No, it wasn't. But I guess you had better scold all the Popes that have used the term in their encyclicals, declarations and "official" documents for using a "Protestant" invented expression.
Pope Paul VI used the term "Roman Catholic Church" in the joint declarations he signed with Patriarch Athenagoras of Constantinople in 1965 and 1967.[77] He also used that term in the declarations he signed with Patriarch Mar Ignatius Yacoub III of the Syrian Orthodox Church on 27 October 1971 and with Archbishop of Canterbury Donald Coggan on 29 April 1977.
Pope John Paul II referred to himself as "the Head of the Roman Catholic Church" (29 September 1979). He called the Church "Roman Catholic" when speaking to the Jewish community in Mainz on 17 November 1980, in a message to those celebrating the 450th anniversary of the Confessio Augustana on 25 June 1980, when speaking to the people of Mechelen, Belgium on 18 May 1985, when talking to representatives of Christian confessions in Copenhagen, Denmark on 7 June 1989, when addressing a delegation from the Ecumenical Patriarchate of Constantinople on 29 June 1989, at a meeting of the Ukrainian Synod in Rome on 24 March 1980, at a prayer meeting in the Orthodox cathedral of Bialystok, Poland on 5 June 1991, when speaking to the Polish Ecumenical Council in Holy Trinity Church, Warsaw 9 June 1991, at an ecumenical meeting in the Aula Magna of the Colégio Catarinense, in Florianópolis, Brazil on 18 October 1991, and at the Angelus in São Salvador da Bahia, Brazil on 20 October 1991.
Pope Benedict XVI called the Church "the Roman Catholic Church" at a meeting in Warsaw on 25 May 2006 and in joint declarations that he signed with Archbishop of Canterbury Rowan Williams on 23 November 2006 and with Patriarch Bartholomew I of Constantinople on 30 November 2006.