You can use WITHIN clause as @johan_larson suggested in above link.
SET … FOR IN… END syntax is for Arrays. In your case it is OBJECT. FOR v WITHIN makes iterate each sub objects . Or Generate Array on the fly.
If you know which level of object you are updating you can try this
As the filed name is dynamic you can generate field names using OBJECT_NAMES() and use that during update of field.
UPDATE data t USE KEYS "03c53a2d-6208-4a35-b9ec-f61e74d81dab"
SET t.metadata.configurations.[v].enabled = false FOR v IN OBJECT_NAMES(t.metadata.configurations) END ;
In above example OBJECT_NAMES(t.metadata.configurations) generates [“AU”, “BE”,“BG”] When field of JSON is referenced .[v] it evaluates v and value become field (special construct no filed name after dot and starts array brackets) The v can be any expression and evaluate to non empty string identifier. So During looping construct t.metadata.configurations.[v].enabled becomes