Does anyone know of anything in the spirit of something like plain text accounting (https://plaintextaccounting.org/) but adapted to integrate the complexities of a wealthy family? I intend to implement something myself, but was interested in knowing whether there was anything like this out there, or to hear from someone with experience with this problem.

The point would be to design something that substitutes for Addepar but with a sensibly organized sqlite db and csvs as "first class" sources of truth (and scripts to handle a variety of common functionality).

So it is really an exercise in understanding the correct architecture of various hierarchies, relationships, and categories in the context of a wealthy family.

All the major software out there just does not seem very good, appear to have a principled handle on the fundamental and primitive relationships and operations that describe a family's financial affairs (everything done on an ad hoc basis). And because of this, entail complete data/platform lock-in.