If you can not find Jesus outside of a church how can you be a Christian..
By following what Christ taught.
“And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.” Mat 6:18
Here Christ says he has established a Church and his Church will not be destroyed.
“But if I tarry long, that thou mayest know how thou oughtest to behave thyself in the house of God, which is the church of the living God, the pillar and foundation of the truth.” 1Tim 3:15
Here the Church is established as the pillar and foundation of truth. There cannot be multiple ‘Truths’ so there cannot be multiple Churches.