Acts 15:1-6 / John 15:1-8
The word "catholic" in a narrow sense may mean the Roman Catholic faith.
But in the broad sense of the word, it means a wide variety of things, all-embracing, diverse, diversified, wide, broad, broad-based, indiscriminate, etc.
Seen in that sense, then it also means that the Roman Catholic Church should also have all those aspects and in many ways she does.
But with the diversity and universality of races, nationalities, languages, cultures, customs and traditions, there will be some inevitable issues.
Such was the case in the 1st reading with the Christian Jews and the Christian non-Jews and the point of contention was about circumcision.
Certainly it was not a small matter so much so that the apostles and elders met to look into the matter.
But the crux of the matter is not so much about the expression of the faith but more about the impression of the faith, i.e. whose mark or imprint is made in the hearts of believers?
In the gospel, Jesus said that He is the true vine and we are the branches.
In our hearts must be marked and imprinted with His word, so that we make our home in Him just as He make His home in us.
Then we will bear fruit in plenty and be all things for all peoples (1 Cor 9:22) so that God will be all in all (1 Cor 15:28).
Then we are indeed truly Catholic in the sense of the word.