I think it depends on where you are.
There has been a lot of controvosy in the Diocese of Portsmouth (UK) because the Dir of liturgy is a composer who set up his own publishing house in the Diocese offices and has attempted to push his own music on parishes, where he then obtains the royalties. The fact that it is vacuous dirge hasn’t escaped a lot of Directors of Music at parish level. If there were any quality control it should have been consigned to the shredder long ago.
The main “authority” on chant is the Benedictine Abbey of Solemnes in France where the musicologists have been entrusted to produce the main volumes of chant that are commonly used as the “standard”. The Liber Usualis is the volume of chant for the EF mass, and they also produce the Graduale for the OF. Other chant traditions (Ambrosian, Dominican, and Coptic) are also standardised from a parent House within that order.
Beyond that I expect that there are diocesan guidelines of varying quality depending on whether their Bp is more traditionally minded or who is in charge of the Liturgy Cttee. Ironically I am a Lay Clerk in an Anglican cathedral choir and in the Anglican church there is far greater musical consistency and a greater appreciation of the role of traditional (and appropriate) music in the liturgy than the majority of RC cathedrals. I’ve been drafted into the cathedral choir in my own diocese a few times (they can’t afford a professional choir but have an amateur choir of reasonable standard) and the DoM is a “trendy nun” who makes them perform music that sounds like a pastiche of Bob Dylan’s 70’s protest songs.