Union with Christ is primary–this never changes:
127. Therefore, let us all enter into closest union with Christ and strive to lose ourselves, as it were, in His most holy soul and so be united to Him that we may have a share in those acts with which He adores the Blessed Trinity with a homage that is most acceptable, and by which He offers to the eternal Father supreme praise and thanks which find an harmonious echo throughout the heavens and the earth, according to the words of the prophet, “All ye works of the Lord, bless the Lord.”[Dan. 3:57] Finally, in union with these sentiments of Christ, let us ask for heavenly aid at that moment in which it is supremely fitting to pray for and obtain help in His name.[Cf. John 16: 3] For it is especially in virtue of these sentiments that we offer and immolate ourselves as a victim, saying, “make of us thy eternal offering.”[Roman Missal, Secret for Mass of the Most Blessed Trinity]
The question for any age, any ideology, any individual: what discernment gets us to this union with Jesus Christ.
The Eucharist is a given, and for two millennia, has been a sure way to the Lord:
128. The divine Redeemer is ever repeating His pressing invitation, “Abide in Me.”[John, 15:4] Now by the sacrament of the Eucharist, Christ remains in us and we in Him, and just as Christ, remaining in us, lives and works, so should we remain in Christ and live and work through Him.
Traditional teaching on the Eucharist reflects the very earliest experience of the apostolic disciples:
129. The Eucharistic Food contains, as all are aware, “truly, really and substantially the Body and Blood together with soul and divinity of our Lord Jesus Christ.”[Council of Trent, Sess. 13, can. 1] It is no wonder, then, that the Church, even from the beginning, adored the body of Christ under the appearance of bread; this is evident from the very rites of the august sacrifice, which prescribe that the sacred ministers should adore the most holy sacrament by genuflecting or by profoundly bowing their heads.
The wording here is very traditional, but it reflects a constant experience that has bound Christians together and to Christ for the entire age of the Lord. The prescribed externals point to an internal orientation–at least this is the ideal posture for Christians.