These rules can vary instance to instance, site to site. Contracting for a schema that works in all of those sites is much harder if they have to share narrower and narrower context rules. It may be that the most practical approach is to separate out the context rules either into the application or into a separately cited document such as TREX, Schematron, etc. We know we need both but not both all the time and in all cases. Again, the monolith definitions can strangle by attempting too much scope of control along multiple axes.
Centralization gives the illusion of efficiency but quite the opposite is the case.
In systems, interfaces that consume system resources making sure every local system is behaving in accordance with global requirements, often when those requirements add nothing to local production. The schema acts as a control. Look at use case for the schema and make very sure the constraints are shared. Otherwise, let the locals add what they need as they need them. Ekam sat.h, Vipraah bahudhaa vadanti.