My Json has always a status
Why declare the "where" clause when creating the index? It would not seem needed if status is always set and so your index will reference all rows in the table.
Thanks for sharing the trick of having the second column in the index determine the key based on the first column. I don't know if/when I might need this, but an interesting solution. Generically, it seems like the below-
create index idx_mytable_jsonb_dependent_fields on public.mytable ( (JsonBField->>'primary_field_to_filter_on'), JsonBField->(JsonBField->>'primary_field_to_filter_on')->>'secondary_field' );
