Earlier quoted context omitted.
Why use Postgres just to store JSON? The entire tooling around Mongo is better for JSON Data. Not to mention the LINQ driver.... And you can’t do updates on individual JSON fields in Postgres.
Yes you can - this is an article crated in 2017 https://www.idalko.com/crud-operations-postgres-jsonb/
The problematic part with PostgresSQL JSONB is modifying a JSONB column content. In any case, we totally replace the old content by a new one. So, the update operations turn to the complex queries that can lose the content. You can avoid this by performing the full JSON reorganization before the persistent operation.
You still don’t have the richness of MongoQuery and the aggregation framework and the tooling around working with JSON data isn’t there. Let alone the native driver support.