I would say that Christians need only the Bible for authoritative doctrine.
But that Bible sets up a church, elders/bishops, deacons, collections, judicial dispute standards, communion, baptisms, church discipline standards. . .so in that sense I believe we need the Church, too.
I do not however think that means that the Church gets to make up doctrines as it goes along. I think the Church must always teach doctrines that submit to Scripture.
“judicial dispute standards”
Of course, “judicial dispute standards” would include “judging them that are within” (1 Corinthians 5), and settling disputes between brothers (1 Corinthians 6, 7).
For suggesting this, it was implied that I would institute a church police force, a church Ghestapo, or an Inquisition, in order to maintain purity in the ordinances of the church. Ministers are certainly set up in the Scriptures. Some would, I suppose, restrict them to nice readings and liturgy, and hearing people’s sins in a confessional, but ignoring the church in the aspect of purity in the ordinances (some say “sacraments”).