I really like this implementation, but it's probably worth mentioning here that RunUO and other tools like it are solving the problem at a layer of abstraction beneath what I was introducing here.

The serialization system I am providing here actually leverages System.Text.Json for reading and writing data — it's more concerned with helping you represent version-able, upgrade-able data models that are also compatible with the hierarchical state machine implementation I use for managing game state.

Wow clicked into the thread to see if anyone might mention RunUO :) it’s the only exposure I’ve had to serialization in C# I always wondered how it ranked compared to other approaches.

Ultima online solved all our problems 25 years ago.