You may find the following of interest as to the RCC ever changing doctrine in 2000 years.
Which Roman Catholic Church are we referring to? In which century, and with what new invention. The list starts on page 3:
https://www.tlchrist.info/keithgreen/boettner_romancatholocism.pdf
I have done research on some of these inventions in other reference works and found this to be accurate, as far as I checked.
SOME ROMAN CATHOLIC HERESIES AND INVENTIONS
and the dates of their adoption over a period of 1,650 years
1. Prayers for the dead: began about A.D. 300.
2. Making the sign of the cross: A.D. 300.
3. Wax candles: about A.D. 320.
4. Veneration of angels and dead saints, and use of images: A.D. 375.
5. The Mass, as a daily celebration: A.D. 394.
6. Beginning of the exaltation of Mary, the term “Mother of God” first applied to her by
the Council of Ephesus: A.D. 431.
7. Priests began to dress differently from laymen: A.D. 500.
8. Extreme Unction: A.D. 526.
9. The doctrine of Purgatory, established by Gregory I: A.D. 593.
10. Latin language, used in prayer and worship, imposed by Gregory I: A.D. 600.
11. Prayers directed to Mary, dead saints, and angels: about A.D. 600.
12. Title of pope, or universal bishop, given to Boniface III by emperor Phocas: A.D. 607
13. Kissing the pope’s foot, began with Pope Constantine: A.D. 709.
14. Temporal power of the popes, conferred by Pepin, king of the Franks: A.D. 750.
15. Worship of the cross, images, and relics: authorized in A.D. 786.
16. Holy water, mixed with a pinch of salt and blessed by a priest: A.D. 850.
17. Worship of St. Joseph: A.D. 890.
18. College of Cardinals established: A.D. 927.
19. Baptism of bells, instituted by pope John XIII: A.D. 965.
20. Canonization of dead saints, first by Pope John XV: A.D. 995.
21. Fasting on Fridays and during Lent: A.D. 998.
22. The Mass, developed gradually as a sacrifice, attendance made obligatory in the 11
th
century.
23. Celibacy of the priesthood, decreed by pope Gregory VII (Hildebrand): A.D. 1079.
24. The Rosary, mechanical praying with beads, invented by Peter the Hermit: A.D. 1090.
25. The Inquisition, instituted by the Council of Verona: A.D. 1184.
26. Sale of Indulgences: A.D. 1190.
27. Transubstantiation, proclaimed by Pope Innocent III: A.D. 1215.
28. Auricular Confession of sins to a priest instead of to God, instituted by Pope Innocent
III, in Lateran Council: A.D. 1215.
29. Adoration of the wafer (Host), decreed by Pope Honorius III: A.D. 1220.
30. Bible forbidden to laymen, placed on the Index of Forbidden Books by the Council of
Toulouse: A.D. 1229.
31. The Scapular, invented by Simon Stock, an English monk: A.D. 1251.
32. Cup forbidden to the people at communion by Council of Constance: A.D. 1414.
33. Purgatory proclaimed as a dogma by the Council of Florence: A.D. 1439.
34. The doctrine of Seven Sacraments affirmed: A.D. 1439.
35. The Ave Maria (part of the last half was completed 50 years later and approved by
Pope Sixtus V at the end of the 16
th
century): A.D. 1508.
36. Jesuit order founded by Loyola: A.D. 1534.
37. Tradition declared of equal authority with the Bible by the Council of Trent: A.D.
1545.
38. Apocryphal books added to the Bible by the Council of Trent: A.D. 1546.
39. Creed of pope Pius IV imposed as the official creed: A.D. 1560.
40. Immaculate Conception of the Virgin Mary, proclaimed by Pope Pius IX: A.D. 1854.
41. Syllabus of Errors, proclaimed by Pope Pius IX and ratified by the Vatican Council;
condemned freedom of religion, conscience, speech, press, and scientific discoveries
which are disapproved by the Roman Church; asserted the pope’s temporal authority over
all civil rulers: A.D. 1864.
42. Infallibility of the pope in matters of faith and morals, proclaimed by the Vatican
Council: A.D. 1870.
43. Public Schools condemned by Pope Pius XI: A.D. 1930.
44. Assumption of the Virgin Mary (bodily ascension into heaven shortly after her death),
proclaimed by Pope Pius XII: A.D. 1950.
45. Mary proclaimed Mother of the Church by Pope Paul VI: A.D. 1965.
Add to these many others: monks, nuns, monasteries, convents, forty days Lent, holy
week, Palm Sunday, Ash Wednesday, All Saints day, Candlemas day, fish day, meat
days, incense, holy oil, holy palms, Christopher medals, charms, novenas, and still others.